Search Results (2,040)

Bone immunity represents a dynamic interface where skeletal homeostasis intersects with systemic immune regulation. We synthesize emerging paradigms by contrasting two functionally distinct microenvironments: the marrow cavity, a hematopoietic and immune cell reservoir, and cancellous bone, a metabolically active hub orchestrating osteoimmune interactions. The marrow cavity not only generates innate and adaptive immune cells but also preserves long-term immune memory through stromal-derived chemokines and survival factors, while cancellous bone regulates bone remodeling via macrophage-osteoclast crosstalk and cytokine gradients. Breakthroughs in lymphatic vasculature identification challenge traditional views, revealing cortical and lymphatic networks in cancellous bone that mediate immune surveillance and pathological processes such as cancer metastasis. Central to bone immunity is the neuro–immune–endocrine axis, where sympathetic and parasympathetic signaling bidirectionally modulate osteoclastogenesis and macrophage polarization. Gut microbiota-derived metabolites, including short-chain fatty acids and polyamines, reshape bone immunity through epigenetic and receptor-mediated pathways, bridging systemic metabolism with local immune responses. In disease contexts, dysregulated immune dynamics drive osteoporosis via RANKL/IL-17 hyperactivity and promote leukemic evasion through microenvironmental immunosuppression. We further propose the “brain–gut–bone axis” as a systemic regulatory framework, wherein vagus nerve-mediated gut signaling enhances osteogenic pathways, while leptin and adipokine circuits link marrow adiposity to inflammatory bone loss. These insights redefine bone as a multidimensional immunometabolic organ, integrating neural, endocrine, and microbial inputs to maintain homeostasis. By elucidating the mechanisms of immune-driven bone pathologies, this work highlights therapeutic opportunities through biomaterial-mediated immunomodulation and microbiota-targeted interventions, paving the way for next-generation treatments in osteoimmune disorders. Full article

Adipose tissue plays a crucial role in the tumor microenvironment (TME), where its secreted extracellular vesicles (EVs) are involved in the complex signaling between tumor cells and surrounding stromal components. This study aims to unravel the mechanisms through which adipocyte-derived EVs influence breast cancer (BC) progression. Human mesenchymal stem cells (hMSCs) were differentiated into adipocytes following a 21-day induction protocol that led to significant accumulation of lipid droplets within the cells. EVs were isolated from the conditioned medium of both hMSC-derived adipocytes and BC cells. Particle size distribution, morphology, and uptake into the recipient cell were investigated via nanoparticle tracking analysis, transmission electron microscopy, and fluorescence microscopy, respectively. Our results show that BC-derived EVs notably impaired cell viability and modulated the expression of key genes involved in apoptosis resistance within stromal cells. On the other hand, stromal-derived EVs significantly altered tumor cell behavior, indicating a dynamic, bidirectional exchange of bioactive signals. These findings underscore the pivotal role of EV-mediated communication in the tumor-stroma interplay, suggesting that adipocyte-cancer cell EV crosstalk contributes to the remodeling of the TME, potentially facilitating tumor progression. Full article

Exercise activates many metabolic and signaling pathways in skeletal muscle and other tissues and cells, causing numerous systemic beneficial metabolic effects. Traditionally recognized for their principal role in oxygen (O₂) transport, erythrocytes have emerged as dynamic regulators of vascular homeostasis. Beyond their respiratory function, erythrocytes modulate vascular tone through crosstalk with other cells and tissues, particularly under hypoxia and physical exercise. This regulatory capacity is primarily mediated through the controlled release in the bloodstream of adenosine triphosphate (ATP) and nitric oxide (NO), two potent vasodilators that contribute significantly to matching oxygen supply with tissue metabolic demand. Emerging evidence suggests that many other erythrocyte-released molecules may act as additional factors involved in tissue-erythrocyte crosstalk. This review highlights erythrocytes as active contributors to exercise-induced adaptations through their exocrine signaling. Full article

Brassinosteroids (BRs) are essential regulators of plant development and stress responses, but the distinct contributions of BR biosynthesis and signaling to hormonal crosstalk remain poorly defined. Here, we investigated the effects of the BR biosynthesis inhibitor brassinazole (BRZ) and the BR-insensitive mutant bri1-6 on endogenous phytohormone profiles in Arabidopsis thaliana. Using multivariate analysis and targeted hormone quantification, we show that BRZ treatment and BRI1 disruption alter hormone balance through partially overlapping but mechanistically distinct pathways. Principal component analysis (PCA) and hierarchical clustering revealed that BRZ and the bri1-6 mutation do not phenocopy each other and that BRZ still alters hormone profiles even in the bri1-6 mutant, suggesting potential BRI1-independent effects. Both BRZ treatment and the bri1-6 mutation tend to influence cytokinins and auxin conjugates divergently. On the contrary, their effects on stress-related hormones converge: BRZ decreases salicylic acid (SA), jasmonic acid (JA), and abscisic acid (ABA) in the WT leaves; similarly, bri1-6 mutants show reduced SA, JA, and ABA. These results indicate that BR biosynthesis and BRI1-mediated perception may contribute independently to hormonal reprogramming, with BRZ eliciting additional effects, possibly via metabolic feedback, compensatory signaling, or off-target action. Hormone correlation analyses revealed conserved co-regulation clusters that reflect underlying regulatory modules. Altogether, our findings provide evidence for a partial uncoupling of BR levels and BR signaling and illustrate how BR pathways intersect with broader hormone networks to coordinate growth and stress responses. Full article

Head and neck cancer (HNC) is highly heterogeneous and difficult to treat, underscoring the need for rapid, patient-specific models. Standard three-dimensional (3D) cultures often lose stromal partners that influence therapy response. We developed a patient-derived system maintaining tumor cells, cancer-associated fibroblasts (CAFs), and cells undergoing partial epithelial–mesenchymal transition (pEMT) for drug sensitivity testing. Biopsies from four HNC patients were enzymatically dissociated. CAFs were directly cultured, and their conditioned medium (CAF-CM) was collected. Cryopreserved primary tumor cell suspensions were later revived, screened in five different growth media under 2D conditions, and the most heterogeneous cultures were re-embedded in 3D hydrogels with varied gel mixtures, media, and seeding geometries. Tumoroid morphology was quantified using a perimeter-based complexity index. Viability after treatment with cisplatin or Notch modulators (RIN-1, recombination signal-binding protein for immunoglobulin κ J region (RBPJ) inhibitor; FLI-06, inhibitor) was assessed by live imaging and the water-soluble tetrazolium-8 (WST-8) assay. Endothelial Cell Growth Medium 2 (ECM-2) medium alone produced compact CAF-free spheroids, whereas ECM-2 supplemented with CAF-CM generated invasive aggregates that deposited endogenous matrix. Matrigel with this medium and single-point seeding gave the highest complexity scores. Two of the three patient tumoroids were cisplatin-sensitive, and all showed significant growth inhibition with the FLI-06 Notch inhibitor, while the RBPJ inhibitor RIN-1 induced minimal change. The optimized scaffold retains tumor–stroma crosstalk and provides patient-specific drug response data within days after operation, supporting personalized treatment selection in HNC. Full article

The epicardium plays a pivotal role in heart development, regeneration, and disease response through its contributions to multiple cardiac lineages and its dynamic paracrine signaling. Recent advances in lineage tracing, single-cell technologies, and, particularly, human pluripotent stem cell (hPSC)-derived cardiac organoid models have illuminated the cellular heterogeneity, developmental plasticity, and intercellular crosstalk of epicardial cells with other cardiac cell types. These models have revealed conserved and divergent mechanisms of epicardial function across species, offering new insights into epicardial–myocardial–endothelial–immune interactions and the regulation of cardiac repair. This review highlights recent key findings from developmental and regenerative studies, integrating them with emerging data from human cardiac organoids to provide an updated framework for understanding epicardial biology and its therapeutic potential. Full article

Soil compaction is a major constraint on global agriculture productivity. It disrupts soil structure, reduces soil porosity and fertility, and increases mechanical impedance, thereby restricting root growth and crop yield. Recent studies on rice (Oryza sativa) reveal that the phytohormone ethylene serves as a primary signal and functions as a hub in orchestrating root response to soil compaction. Mechanical impedance promotes ethylene biosynthesis and compacted soil impedes ethylene diffusion, resulting in ethylene accumulation in root tissues and triggering a complex hormonal crosstalk network to orchestrate root system architectural modification to facilitate plant adaptation to compacted soil. This review summarizes the recent advances on rice root adaptation response to compacted soil and emphasizes the regulatory network triggered by ethylene, which will improve our understanding of the role of ethylene in root growth and development and provide a pathway for breeders to optimize crop performance under specific agronomic conditions. Full article

Background/Objectives: Colorectal cancer (CRC) is a leading cause of cancer-related mortality worldwide. Iron metabolism and chronic inflammation are two interrelated processes that significantly influence the initiation and progression of CRC. Iron is essential for cell proliferation, but its excess promotes oxidative stress and DNA damage, while inflammation driven by cytokine-regulated pathways accelerates tumourigenesis. We therefore conducted this narrative review to collate the available evidence on the link between iron homeostasis and inflammatory signalling in CRC and highlight potential diagnostic and therapeutic applications. Methods: This narrative review of preclinical and clinical studies explores the molecular and cellular pathways that connect iron regulation and inflammation to CRC. Key regulatory molecules, such as the transferrin receptor (TFRC), ferroportin (SLC40A1), ferritin (FTH/FTL), hepcidin, and IL-6, were reviewed. Additionally, we summarised the findings of transcriptomic, epigenomic, and proteomic studies. Relevant therapeutic approaches, including iron chelation, ferroptosis induction, and anti-inflammatory strategies, were also discussed. Results: Evidence suggests that CRC cells exhibit altered iron metabolism, marked by the upregulation of transferrin receptor (TFRC), downregulation of ferroportin, and dysregulated expression of ferritin. Inflammatory mediators such as IL-6 activate hepcidin and STAT3 signalling, which reinforce intracellular iron retention and oxidative stress. Increased immune evasion, epithelial proliferation, and genomic instability appear to be linked to the interaction between inflammation and iron metabolism. Other promising biomarkers include ferritin, hepcidin, and composite gene expression signatures; however, their clinical application remains limited. Although several preclinical studies support the use of targeted iron therapies and combination approaches with anti-inflammatory agents or immunotherapy, there is a lack of comprehensive clinical validation confirming their efficacy and safety in humans. Conclusion: Although preclinical studies suggest that iron metabolism and inflammatory signalling form an interconnected axis closely linked to CRC, translating this pathway into reliable clinical biomarkers and effective therapeutic strategies remains a significant challenge. Future biomarker-guided clinical trials are essential to determine the clinical relevance and to establish precision medicine strategies targeting the iron–inflammation crosstalk in CRC. Full article

The morphogenesis of the primordial gut relies on signaling pathways such as Wnt, FGF, Notch, Hedgehog, and Hippo. Reciprocal crosstalk between the endoderm and mesoderm is integrated into the signaling pathways, resulting in craniocaudal patterning. These pathways are also involved in adult intestinal homeostasis including cell proliferation and specification of cell fate. Perturbations in this process can cause growth disturbances manifesting as adenomas, serrated lesions, and cancer. Significant differences have been observed between right and left colon cancers in the hindgut, and between the jejunoileum, appendix, and right colon in the midgut. The question is to what extent the embryology of the mid- and hindgut contributes to differences in the underlying tumor biology. This review examines the precursor lesions and consensus molecular subtypes (CMS) of colorectal cancer (CRC) to highlight the significance of embryology and tumor microenvironment (TME) in CRC. The three main precursor lesions, i.e., adenomas, serrated lesions, and inflammatory bowel disease-associated dysplasia, are linked to the CMS classification, which is based on transcriptomic profiling and clinical features. Both embryologic and micro-environmental underpinnings of the mid- and hindgut contribute to the differences in the tumors arising from them, and they may do so by recapitulating embryonic signaling cascades. This manifests in the range of CRC CMS and histologic cancer subtypes and in tumors that show multidirectional differentiation, the so-called stem cell carcinomas. Emerging evidence shows the limitations of CMS particularly in patients on systemic therapy who develop drug resistance. The focus is thus transitioning from CMS to specific components of the TME. Full article

Objectives: Emerging evidence suggests that propolis possesses significant anti-obesity properties. While gut hormones and microbiota are known to play crucial roles in obesity development, the specific mechanisms through which propolis exerts its effects via the gut hormone axis remain poorly characterized. Methods: A high-fat diet (HFD) rat model was established to investigate the regulatory effects of propolis. After 10 weeks of intervention, blood serum, liver, colon tissues, and luminal contents were analyzed for metabolic parameters, gene expression of gut hormones and AMPK pathway markers, microbial community structure, and short-chain fatty acid production. Results: Propolis effectively mitigated HFD-induced metabolic disturbances, including excessive weight gain, adipose tissue accumulation, hyperlipidemia, and hepatic dysfunction. These improvements were associated with significant upregulation of the AMPK pathway. Importantly, propolis enhanced intestinal barrier integrity and differentially modulated gut hormone expression by increasing the mRNA levels of Cck, Gip, and Ghrl, and decreasing Lep and Gcg levels. 16S rRNA sequencing analysis revealed that propolis administration selectively enriched butyrate- and propionate-producing bacterial species. Correlation analysis further identified the Eubacterium brachy group as a pivotal microbial mediator in the propolis-modulated gut microbiota–gut hormone–liver AMPK axis. Conclusions: Our findings establish that propolis ameliorates obesity-related metabolic disorders by orchestrating crosstalk among gut microbiota, enteroendocrine hormones, and hepatic AMPK signaling. These results elucidate a novel mechanistic pathway in rodents; however, their direct translatability to humans requires further clinical investigation. This tripartite axis offers a mechanistic foundation for developing microbiota-targeted anti-obesity therapies. Full article

Background/Objective: Systemic inflammation is a hallmark of end-stage renal disease (ESRD) and contributes to the high burden of cardiovascular morbidity and mortality in hemodialysis (HD) patients. The systemic immune–inflammation index (SII), derived from peripheral neutrophil, lymphocyte, and platelet counts, has emerged as a promising biomarker of immune–inflammatory status. This study aimed to assess the acute effect of a single HD session on systemic inflammation and to identify metabolic predictors associated with this response. Methods: In this single-center observational before–after study, 44 chronic HD patients were enrolled. Blood samples were collected immediately before and after a single HD session. SII was calculated as platelet count × neutrophil count/lymphocyte count. Subgroup analyses were conducted based on renal disease etiology and diabetic status. Multivariable linear regression models identified baseline predictors of SII variation. Results: Median SII significantly decreased post-HD in the overall cohort (from 553.4 [342.6–847.5] to 449.1 [342.6–866.6], p = 0.001), with a more pronounced reduction in patients with cardiometabolic etiologies (from 643.4 [353.3–1360.0] to 539.1 [324.8–1083.4], p = 0.007) and diabetes (from 671.1 [408.7–1469.1] to 458.3 [285.7–1184.4], p = 0.028), but not in those with nephroangiosclerosis (p = 0.182). Baseline total cholesterol (p = 0.001) and gamma-glutamyl transferase (p = 0.034) were positively associated with smaller reductions in SII, while higher baseline glycaemia predicted a greater decrease in post-dialysis SII (p = 0.021). Conclusions: HD acutely modulates systemic inflammation, as reflected by reduction in SII. The magnitude of this response is significantly influenced by individual metabolic profiles. These findings highlight the relevance of metabolic–immune crosstalk in ESRD and suggest that SII may serve as a dynamic biomarker integrating inflammatory and metabolic signals, deserving further validation in larger, outcome-driven studies. Full article

Background/Objectives: The interaction between brain-metastasizing melanoma cells and surrounding microglia shapes the immune tumor microenvironment and influences tumor progression. Gene expression analysis revealed that sphingosine-1-phosphate receptor 1 (S1PR1), encoding the S1P1 receptor, is upregulated in microglia upon interaction with melanoma cells. Here, we investigated the functions of S1P1 in microglia and its contribution to melanoma–microglia crosstalk. Methods: We examined the effects of S1P1 inhibition on microglia and four brain-metastasizing human melanoma cell lines in monocultures and co-cultures using the selective S1P1 antagonist NIBR0213 and S1PR1 gene knockdown. Results: We found that melanoma-secreted IL-6 upregulated S1PR1 expression in microglia. S1P1 inhibition increased expression of CD32, CD150, and CD163 in microglia; however, CD150 and CD163 upregulation was abolished in the presence of melanoma cells. S1P1 inhibition downregulated immunosuppressive and anti-inflammatory factors in microglia, including CD274, SOCS3, TGFBR1, TGFBR2, and JunB, promoting a pro-inflammatory phenotype. It also reduced viability of both melanoma and microglia cells, inducing apoptosis in melanoma-associated microglia, possibly via downregulation of CH25H, an upstream regulator of SREBPs. In co-cultures, melanoma cells were more sensitive than microglia to NIBR0213-induced growth arrest. In 3D spheroid cultures, NIBR0213 delayed melanoma–microglia aggregation. Combined treatment with the BRAF inhibitor Vemurafenib and NIBR0213 enhanced Vemurafenib efficacy in three of four melanoma lines. Conclusions: S1P1 contributes to the immunosuppressive phenotype of microglia. Inhibiting the S1P/S1P1 axis impairs viability and crosstalk between melanoma cells and tumor-activated microglia, offering a potential therapeutic strategy for melanoma brain metastases. Full article

Toll-like receptor 3 (TLR3) initiates antiviral and inflammatory responses exclusively through the adaptor protein TRIF (TIR-domain-containing adapter-inducing interferon-β). In contrast, MyD88 (myeloid differentiation primary response 88), a central adaptor for most other TLRs, is traditionally considered dispensable for TLR3 signaling. Here, we demonstrate that MyD88 directly contributes to TLR3-mediated NF-κB activation and cytokine production in macrophages. Bone marrow-derived macrophages (BMDMs) from MyD88 deficient mice exhibited significantly attenuated NF-κB activation in response to the TLR3 agonist polyinosinic–polycytidylic acid (poly(I:C)) compared to wild-type cells, as evidenced by the reduced phosphorylation of NF-κB p65 and IκBα, as well as IκBα degradation. Consistently, pro-inflammatory cytokine production, including IL-6, TNF-α, and IFN-β, was attenuated in MyD88-deficient BMDMs in vitro following stimulation by poly(I:C) or poly(A:U), another TLR3 agonist. Blood concentrations of IL-6, TNF-α, and IFN-β were significantly reduced in both TRIF-deficient mice and MyD88-deficient mice challenged by the i.p. injection of poly(I:C). Mechanistic analyses revealed that MyD88 physically associates with activated TLR3 upon poly(I:C) stimulation, and that TLR3 engagement triggered MyD88 oligomerization, which was absent in TLR3 or TRIF deficient macrophages. Our findings highlight a previously unrecognized dual-adaptor mechanism for TLR3, wherein MyD88 recruitment amplifies NF-κB signaling dynamics by bridging TLR3 to the canonical NF-κB activation cascade and robust cytokine induction. This study expands the paradigm of TLR3 signaling by establishing MyD88 as a direct contributor to TLR3-driven innate immune responses, offering new insight into cross-talk between MyD88-dependent and -independent pathways. Full article

Neuropathic pain is a chronic condition driven by intertwined mechanisms of oxidative stress, inflammation, and cellular senescence. Nerve injury and metabolic stress elevate reactive oxygen and nitrogen species, disrupt mitochondrial function, and activate the DNA-damage response, which stabilizes p53 and induces p16/p21-mediated cell-cycle arrest. These events promote a senescence-associated secretory phenotype (SASP) rich in cytokines, chemokines, and prostanoids that amplify neuroimmune signaling. In the spinal dorsal horn and dorsal root ganglia, microglia and astroglia respond to redox imbalance and danger cues by engaging NF-κB and MAPK pathways, increasing COX-2–dependent prostaglandin synthesis, and releasing mediators such as IL-1β and BDNF that enhance synaptic transmission and reduce inhibitory tone through KCC2 dysfunction. At the periphery, persistent immune-glial cross-talk lowers activation thresholds of nociceptors and sustains ectopic firing, while impaired autophagy and mitophagy further exacerbate mitochondrial dysfunction and ROS production. Collectively, these processes establish a feed-forward loop in which redox imbalance triggers senescence programs and SASP, SASP perpetuates neuroinflammation, and neuroinflammation maintains central sensitization—thereby consolidating a self-sustaining redox–senescence–inflammatory circuit underlying neuropathic pain chronicity. Full article

Aluminum (Al) toxicity is a major limiting factor for plant growth and development in acidic soils. Melatonin, a plant growth regulator and signaling molecule, enhances resistance to multiple stresses. Recent studies show that melatonin alleviates Al toxicity through several complementary mechanisms. Here, we first outline the physiological and molecular impacts of Al stress and the external and internal strategies plants use to cope with it. We then summarize melatonin biosynthesis and its broader roles in stress adaptation. We focus on recent advances in melatonin-mediated mitigation of Al toxicity, highlighting four principal mechanisms: (i) the activation of antioxidant defense systems, (ii) the stimulation of organic acid anion exudation that chelates Al in the rhizosphere, (iii) the modification of cell wall composition to reduce Al binding sites, and (iv) the promotion of intracellular Al sequestration. We also discuss the crosstalk between melatonin and nitric oxide, as well as interactions with phytohormone signaling. Collectively, this review comprehensively synthesizes the current understanding regarding the role of melatonin in alleviating Al toxicity in plants, offering a promising strategy for crop production in acidic environments. Full article