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Memory cells are central to the adaptive immune system’s ability to remember and respond effectively to previously encountered pathogens. While memory cells provide robust protection against infections, they can also contribute to autoimmunity when regulation fails. Here, we review the roles of memory T and B cells in infection and autoimmunity, focusing on their differentiation, activation, effector functions, and underlying regulatory mechanisms. We elaborate on the precise mechanisms by which memory cells contribute to autoimmune diseases, highlighting insights from current research on how pathogenic memory responses are formed and sustained in autoimmunity. Finally, we explore potential therapeutic strategies aimed at modulating memory cells to prevent or treat autoimmune disorders, including B cell-depleting therapies (e.g., Rituximab), T cell-targeting agents (e.g., Abatacept), and cytokine inhibitors (e.g., IL-17 or IL-23 blockers) that are currently used in diseases such as rheumatoid arthritis, multiple sclerosis, and psoriasis.

Atherosclerosis remains a leading cause of cardiovascular morbidity and mortality worldwide. While traditionally attributed to lipid accumulation, endothelial dysfunction, and inflammation, growing evidence implicates the lymphatic system as a key regulator of vascular homeostasis and plaque stability. Recent experimental data suggest that restoring lymphatic function may represent a novel therapeutic avenue in atherosclerosis. Recombinant VEGF-C variants and nanoparticle-based gene delivery systems selectively have been shown to induce lymphangiogenesis and improve lipid clearance without triggering abnormal angiogenesis. Similarly, Apolipoprotein A-I infusions have been demonstrated to strengthen lymphatic endothelial junctions, enhance vessel contractility, and facilitate the removal of cholesterol and inflammatory cells from atherosclerotic lesions. This comprehensive review aims to present recent findings from preclinical and clinical trials and studies on investigational pharmacological therapies, explore the interrelationship between atherosclerosis and the lymphatic system, and highlight potential avenues for future research.

Pulmonary arterial hypertension (PAH) is a progressive cardiovascular disease characterized by elevated pulmonary arterial pressure, leading to right heart failure and death. Despite advancements in diagnosis and treatment, it remains incurable, and its mechanisms are poorly understood. This study aimed to integrate multi-omics data analysis and machine learning techniques to uncover the molecular characteristics and subtypes of PAH, providing insights into precise diagnosis and therapeutic strategies. We employed consensus clustering to classify PAH patients into subgroups based on multi-omics data. Differential expression and enrichment analyses were conducted to identify key genes and pathways. Machine learning models were developed to predict PAH subtypes and assess their diagnostic performance. PAH patients were divided into two subgroups: C1 and C2. The C2 subgroup showed significantly upregulated hypoxia-related genes, indicating distinct pathogenic mechanisms. Key genes associated with hypoxia, immune regulation, and inflammation were identified, alongside enriched pathways such as TNF, IL-17, and HIF-1 in the C2 subgroup. Machine learning models achieved high accuracy (AUC > 0.85) in distinguishing hypoxia-associated subtypes, supporting their utility for precise diagnosis. Potential therapeutic targets were identified in the TNF and HIF-1 pathways. This study provides novel insights into PAH’s molecular subtypes and their distinct mechanisms, offering diagnostic tools and potential therapeutic targets for personalized treatment. Validation in larger cohorts and experimental studies is essential to confirm the identified biomarkers and pathways.

Preeclampsia is a leading cause of maternal and perinatal morbidity and mortality worldwide. Emerging evidence implicates gut and vaginal microbiota dysbiosis in preeclampsia pathogenesis through its roles in immune regulation, inflammation, and placental function. This review explores the mechanisms linking microbiota alterations to preeclampsia and evaluates the therapeutic potential of microbiota-targeted interventions. A systematic search using MeSH terms related to “preeclampsia”, “microbiota”, and “dysbiosis” identified studies on microbiota and preeclampsia pathophysiology. Data extraction focused on microbial alterations and mechanistic insights. Gut dysbiosis, characterized by reduced beneficial bacteria and short-chain fatty acid production, weakens the intestinal barrier, exacerbates systemic inflammation, and impairs placental development. Vaginal dysbiosis, marked by reduced Lactobacillus species, promotes local inflammation, increasing placental dysfunction risk. Therapeutic strategies, including probiotics, prebiotics, and dietary modifications, show promise in restoring microbial balance and mitigating preeclampsia risk. Microbiota dysbiosis significantly contributes to preeclampsia pathogenesis through inflammation, endothelial dysfunction, and placental impairment. Interventions targeting microbial balance, such as probiotics and dietary modifications, show promise for prevention, but further research and large-scale trials are essential to validate their efficacy and safety.

Antigen presenting cells (APCs) of the innate immune system sense a wide range of pathogens via pattern recognition receptors (PRRs). Engagement of certain PRRs can induce production of pro-inflammatory mediators that facilitate effective clearance of pathogen. Toll-like receptors (TLRs) are a well described group of PRRs that belong to the TLR/Interleukin-1 receptor (IL-1R) superfamily. However, TLR/IL-1R induction of pro-inflammatory mediators must be regulated to prevent excessive inflammation and tissue damage. One molecule of recent interest that is known to inhibit TLR/IL-1R signaling is interleukin-1 receptor associated kinase (IRAK)-M, also known as IRAK-3. IRAK-M is expressed in a number of immune and epithelial cells types, and through its inhibition of pro-inflammatory cytokine production, IRAK-M can regulate immune homeostasis and tolerance in a number of infectious and non-infectious diseases. Furthermore, use of IRAK-M deficient animals has increased our understanding of the importance of IRAK-M in regulating immune responsiveness to a variety of pathogens. Although IRAK-M expression is typically induced through TLR signaling, IRAK-M can also be expressed in response to various endogenous and exogenous soluble factors as well as cell surface and intracellular signaling molecules. This review will focus on clinical scenarios in which expression of IRAK-M is beneficial (as in early sepsis) and those situations where IRAK-M expression is harmful to the host (as in cancer and following bone marrow transplant). There is strong rationale for therapeutic targeting of IRAK-M for clinical benefit. However, effective targeting will require a greater understanding of the transcriptional regulation of this gene.

During metastasis, cancer cells undergo epithelial-mesenchymal transition (EMT) in response to transforming growth factor-β (TGF-β), which is abundant in the tumor microenvironment, and acquire invasive and metastatic potentials. Metastasis to distant organs requires intravascular invasion and extravasation of cancer cells, which is accompanied by the disruption of the adhesion between vascular endothelial cells. Cancer cell-derived extracellular vesicles (EVs) have been suggested to induce the destabilization of normal blood vessels at the metastatic sites. However, the roles of EVs secreted from cancer cells that have undergone EMT in the destabilization of blood vessels remain to be elucidated. In the present study, we characterized EVs secreted by oral cancer cells undergoing TGF-β-induced EMT and elucidated their effects on the characteristics of vascular endothelial cells.BACKGROUNDDuring metastasis, cancer cells undergo epithelial-mesenchymal transition (EMT) in response to transforming growth factor-β (TGF-β), which is abundant in the tumor microenvironment, and acquire invasive and metastatic potentials. Metastasis to distant organs requires intravascular invasion and extravasation of cancer cells, which is accompanied by the disruption of the adhesion between vascular endothelial cells. Cancer cell-derived extracellular vesicles (EVs) have been suggested to induce the destabilization of normal blood vessels at the metastatic sites. However, the roles of EVs secreted from cancer cells that have undergone EMT in the destabilization of blood vessels remain to be elucidated. In the present study, we characterized EVs secreted by oral cancer cells undergoing TGF-β-induced EMT and elucidated their effects on the characteristics of vascular endothelial cells.Induction of EMT by TGF-β in human oral cancer cells was assessed using quantitative RT-PCR (qRT-PCR) and immunocytochemistry. Oral cancer cell-derived EVs were isolated from the conditioned media of oral cancer cells that were treated with or without TGF-β using ultracentrifugation, and characterized using nanoparticle tracking analysis and immunoblotting. The effects of EVs on human umbilical artery endothelial cells were examined by qRT-PCR, cellular staining, and permeability assay. The significant differences between means were determined using a t-test or one-way analysis of variance with Tukey's multiple comparisons test.METHODSInduction of EMT by TGF-β in human oral cancer cells was assessed using quantitative RT-PCR (qRT-PCR) and immunocytochemistry. Oral cancer cell-derived EVs were isolated from the conditioned media of oral cancer cells that were treated with or without TGF-β using ultracentrifugation, and characterized using nanoparticle tracking analysis and immunoblotting. The effects of EVs on human umbilical artery endothelial cells were examined by qRT-PCR, cellular staining, and permeability assay. The significant differences between means were determined using a t-test or one-way analysis of variance with Tukey's multiple comparisons test.Oral cancer cells underwent EMT in response to TGF-β as revealed by changes in the expression of epithelial and mesenchymal cell markers at both the RNA and protein levels. Oral cancer cells treated with TGF-β showed increased EV production and altered EV composition when compared with untreated cells. The EVs that originated from cells that underwent EMT by TGF-β induced endothelial-mesenchymal transition, which was characterized by the decreased and increased expression of endothelial and mesenchymal cell markers, respectively. EVs derived from oral cancer cells also induced intercellular gap formation which led to the loss of endothelial cell barrier stability.RESULTSOral cancer cells underwent EMT in response to TGF-β as revealed by changes in the expression of epithelial and mesenchymal cell markers at both the RNA and protein levels. Oral cancer cells treated with TGF-β showed increased EV production and altered EV composition when compared with untreated cells. The EVs that originated from cells that underwent EMT by TGF-β induced endothelial-mesenchymal transition, which was characterized by the decreased and increased expression of endothelial and mesenchymal cell markers, respectively. EVs derived from oral cancer cells also induced intercellular gap formation which led to the loss of endothelial cell barrier stability.EVs released from oral cancer cells that underwent TGF-β-induced EMT target endothelial cells to induce vascular destabilization. Detailed characterization of oral cancer-derived EVs and factors responsible for EV-mediated vascular instability will lead to the development of agents targeting metastasis.CONCLUSIONSEVs released from oral cancer cells that underwent TGF-β-induced EMT target endothelial cells to induce vascular destabilization. Detailed characterization of oral cancer-derived EVs and factors responsible for EV-mediated vascular instability will lead to the development of agents targeting metastasis.

The microenvironment of the thymus is composed of a group of stromal cells that include endoderm-derived thymic epithelial cells (TECs) and mesenchymal stromal cells such as fibroblasts and serves as a site for the development of T cells. TECs are known to play an essential role in T cell differentiation and selection. Mesenchymal stromal cells have been less studied in terms of their immunological significance compared to TECs. Recently, new technologies have made it possible to identify and characterize mesenchymal stromal cells in the thymus, revealing their unique functions in thymic organogenesis and T cell development. This review outlines the current views on mesenchymal stromal cells in the thymus, particularly highlighting the newly discovered function of thymic fibroblasts in T cell repertoire selection.The microenvironment of the thymus is composed of a group of stromal cells that include endoderm-derived thymic epithelial cells (TECs) and mesenchymal stromal cells such as fibroblasts and serves as a site for the development of T cells. TECs are known to play an essential role in T cell differentiation and selection. Mesenchymal stromal cells have been less studied in terms of their immunological significance compared to TECs. Recently, new technologies have made it possible to identify and characterize mesenchymal stromal cells in the thymus, revealing their unique functions in thymic organogenesis and T cell development. This review outlines the current views on mesenchymal stromal cells in the thymus, particularly highlighting the newly discovered function of thymic fibroblasts in T cell repertoire selection.

Key Points Hypoxia and inflammation are frequently co-incidental microenvironmental features of sites of concentrated physiological or pathological immune activity. Hypoxia activates hypoxia-inducible factor, which is a major regulator of multiple aspects of immune cell function. Consequently, hypoxia plays a key role in the regulation of immunity and inflammation. The impact of hypoxia on immunity and inflammation is site-specific and cell type-specific. Pharmacological hydroxylase inhibition, which activates hypoxia-sensitive pathways, is profoundly protective in multiple models of inflammation. Hypoxia is a microenvironmental feature that is associated with physiological and pathological immunological niches. In this Review, Taylor and Colgan summarize the effects of physiological and pathological hypoxia on immune cells and processes and discuss the possibility of therapeutically targeting hypoxia-sensitive pathways. Immunological niches are focal sites of immune activity that can have varying microenvironmental features. Hypoxia is a feature of physiological and pathological immunological niches. The impact of hypoxia on immunity and inflammation can vary depending on the microenvironment and immune processes occurring in a given niche. In physiological immunological niches, such as the bone marrow, lymphoid tissue, placenta and intestinal mucosa, physiological hypoxia controls innate and adaptive immunity by modulating immune cell proliferation, development and effector function, largely via transcriptional changes driven by hypoxia-inducible factor (HIF). By contrast, in pathological immunological niches, such as tumours and chronically inflamed, infected or ischaemic tissues, pathological hypoxia can drive tissue dysfunction and disease development through immune cell dysregulation. Here, we differentiate between the effects of physiological and pathological hypoxia on immune cells and the consequences for immunity and inflammation in different immunological niches. Furthermore, we discuss the possibility of targeting hypoxia-sensitive pathways in immune cells for the treatment of inflammatory disease.

Key Points The unfolded protein response (UPR) has an important role in the differentiation and maturation of various immune cells and is crucial for immune cell function, such as cytokine production by macrophages and cross-presentation by dendritic cells, for example. Innate immune signalling differentially affects the three arms of the UPR to optimize inflammatory responses, while simultaneously inhibiting the activation of the terminal UPR, which is associated with cell death. This allows the cell to survive and manage temporary increases in protein production during immune responses to pathogens. In complex autoimmune diseases, chronic activation of the UPR can function as the nidus for the development of inflammation. UPR activation triggers inflammatory responses mainly through nuclear factor-κB (NF-κB) activation, phosphorylation of JUN N-terminal kinase (JNK), activation of the inflammasome and direct interaction of downstream UPR targets with the promoters of inflammatory cytokine genes. UPR activation in cancer cells may interfere with antitumour immunity, which indicates that manipulating UPR signalling could boost antitumour immune responses. The UPR is amenable to therapeutic manipulation to either promote its beneficial homeostasis-inducing properties and/or inhibit its inflammation-inducing activities in the setting of unresolved endoplasmic reticulum (ER) stress. The unfolded protein response pathway that is induced by endoplasmic reticulum (ER) stress has important roles in immune cell development and function, which have led to new insights into the pathogenesis of inflammatory diseases. The unfolded protein response (UPR) is a highly conserved pathway that allows the cell to manage endoplasmic reticulum (ER) stress that is imposed by the secretory demands associated with environmental forces. In this role, the UPR has increasingly been shown to have crucial functions in immunity and inflammation. In this Review, we discuss the importance of the UPR in the development, differentiation, function and survival of immune cells in meeting the needs of an immune response. In addition, we review current insights into how the UPR is involved in complex chronic inflammatory diseases and, through its role in immune regulation, antitumour responses.

Key Points Mucins are highly O -glycosylated molecules that have gel-like properties. The mucin family consists of transmembrane mucins and gel-forming mucins. The transmembrane mucins cover the apical surfaces of the enterocytes and form the glycocalyx. The gel-forming mucins are secreted from goblet cells as large multimers that form the mucus skeleton and cover all epithelial surfaces. Mucus in the small intestine forms a diffusion barrier where antimicrobial substances keep the epithelium free from microorganism. Mucus in the colon forms a dense inner mucus layer that bacteria are unable to penetrate, creating a bacteria-free zone at the epithelial surface. Some, but not all, bacteria stimulate the formation of a functional mucus system with removable mucus in the small intestine and a stratified impenetrable inner mucus layer in colon. Mucus in the intestine creates a niche for bacteria, with digestible glycans providing a stable energy source, but mucus also traps and removes bacteria. Bacteria in loose mucus are planktonic and less virulent. The small intestinal goblet cells can sample luminal material during mucus secretion and transfer the antigens to lamina propria dendritic cells, something that also happens in the colon if bacterial numbers are decreased. This communication with the immune system has tolerogenic effects. Intestinal pathogens have mechanisms that allow them to circumvent the mucus protection to reach the epithelium. These include good motility and secretion of enzymes that can degrade the otherwise protease-resistant mucins. This Review describes the unique properties of mucus and mucins, with a focus on the intestine. Mucus and mucus-producing goblet cells contribute to our innate immune defences and, in turn, are regulated by the immune system. The authors discuss the link between defective mucus production and increased susceptibility to infection and inflammatory disease. A number of mechanisms ensure that the intestine is protected from pathogens and also against our own intestinal microbiota. The outermost of these is the secreted mucus, which entraps bacteria and prevents their translocation into the tissue. Mucus contains many immunomodulatory molecules and is largely produced by the goblet cells. These cells are highly responsive to the signals they receive from the immune system and are also able to deliver antigens from the lumen to dendritic cells in the lamina propria. In this Review, we will give a basic overview of mucus, mucins and goblet cells, and explain how each of these contributes to immune regulation in the intestine.