Disruption of iron homeostasis is associated with multiple diseases. It has been found that patients with genetic iron overload develop massive iron deposition in the pancreas. However, few studies have focused on the effect of secondary iron overload on the pancreas. The objective of the present study was to investigate the pathogenic consequences of secondary iron overload in mice. An iron overload mouse model was constructed by intraperitoneal injection of 120 mg/kg body weight of iron dextran every other week for 12 weeks. Iron deposition, immunocyte infiltration, fibrosis, oxidative stress and ferroptosis were assessed using Prussian blue staining, immunohistochemical analysis, Masson staining, Sirius red staining, RT‑qPCR analysis and western blot analysis. It was found that iron‑overloaded mice showed pancreatic iron overload, together with elevated gene expression of the iron storage factor ferritin H, and decreased expression of the iron transportation mediator divalent metal transporter 1, ferroportin 1 and transferrin receptor. Iron‑overloaded mice developed mild pancreatitis with increased serum amylase and lipase activities, as well as elevated gene expression levels of pro‑inflammatory cytokines, including interleukin (IL)‑1β, IL‑6 and inducible nitric oxide synthase. Acinar atrophy, massive immunocyte infiltration and pancreatic fibrosis were noted in the iron‑overloaded mice. As an underlying mechanism, iron‑overloaded mice showed increased pancreatic oxidative stress, with an elevated malondialdehyde level, and decreased SOD and glutathione peroxidase activity. Furthermore, iron overload led to ferroptosis with promoted expression of cytochrome c oxidase subunit II, and decreased transcripts of glutathione peroxidase 4 and solute carrier family 7 member 11. These results provided evidence that multiple intraperitoneal injections of iron dextran in mice lead to iron overload‑induced chronic pancreatitis, which suggested that secondary iron overload is a risk factor for pancreatitis and highlights the importance of iron in maintaining the normal functions of the pancreas.

Hepatic immune tolerance might contribute to the development of therapeutic resistance to immunotherapy. However, addressing this issue is challenging since the efficacy of immunotherapy in the context of liver metastasis (LM) remains poorly studied. Here, we aimed to establish an LM common immune feature (LMCIF) score to quantify the characteristics of LM immunotolerance across cancer types for assisting clinical disease management. Large-scale clinical data were collected to identify the prognosis of LM. Multi-omics datasets of metastatic cancers with LM special immune-related pathways (LMSIPs) from the Molecular Signatures Database (MSigDB)were used to obtain an LMCIF cluster. Based on differential expression genes (DEGs), a novel LMCIF score for the LMCIF cluster was constructed. In addition, multi-omics, and immunohistochemistry (IHC) data from the public and in-house cohorts were used to explore the features of LM, and LMCIF score. Patients with LM had a worse prognosis and significantly lower infiltration of immune cells than patients with metastasis to other organs when analyzed with combined clinical and RNA sequencing data. After extracting the LMCIF cluster from 373 samples by utilizing 29 LMSIPs and validating them in a microarray cohort, an LMCIF score was established to confirm the role of the immunosuppressive environment as a contributor to the poor prognosis of LM across cancer types. Moreover, this LMCIF score could be used to predict the immune response of cancer patients undergoing immunotherapy. Finally, we identified that the majority of the 31 LMCIF genes exhibited a negative correlation with TME cells in LM patients, one of them, KRT19, which possessed the strongest positive correlation with LMCIF score, was confirmed to have an immunosuppressive effect through IHC analysis. Our results suggest that LM across cancer types share similar immunological profiles that induce immunotolerance and escape from immune monitoring. The novel LMCIF score represents a common liver metastasis immune cluster for predicting immunotherapy response, the results of which might benefit clinical disease management.

Purpose: Lipocalin-2 (Lcn2) is an acute-phase protein and elevated in several inflammatory diseases. This study aimed to determine whether Lcn2 alleviates inflammation and explore the underlying cellular mechanisms. Methods: C57BL/6 Lcn2-deficient (Lcn2^−/-) male mice were intraperitoneally injected with lipopolysaccharide (LPS) to build systemic inflammation model. The inflammatory processes were investigated. The morphology of villi was measured by scanning electron microscopy (SEM). The levels of inflammatory factors were detected by ELISA and qPCR analysis. The production of Lcn2 was determined with immunofluorescence staining by confocal microscope. The molecular mechanism of Lcn2 in bone marrow-derived macrophages (BMDMs) was analyzed by mass spectrometry (MS)-based quantitative proteomic analysis. Results: Compared to wild-type (WT) mice injected with LPS, Lcn2^−/- mice injected with LPS showed increased inflammatory damage in jejunum and ileum, and significantly elevated the levels of multiple pro-inflammatory cytokines. After determining that Lcn2 was mainly located in the cytoplasm of macrophages, we isolated BMDMs from Lcn2^−/- mice to evaluate their function. During LPS challenge, transcripts of pro-inflammatory cytokines were all significantly increased in BMDMs from Lcn2^−/- mice, while those of anti-inflammatory cytokines were significantly decreased when compared with the cytokines in BMDMs from WT mice. A label-free relative quantitation proteomics analysis showed that LPS-treated BMDMs from Lcn2^−/- mice had elevated levels of pro-inflammatory pathways, but reduced phagocytosis and autophagy when compared with LPS-treated BMDMs from WT mice. Conclusion: These findings demonstrated that Lcn2 was a potent protective factor in response to systemic inflammation and might be an indispensable factor for macrophage functions.

Severe acute pancreatitis (SAP) is a life-threatening condition characterized by excessive reactive oxygen species (ROS) production and impaired mitochondrial function, resulting from disrupted autophagic flux. Current clinical treatment for SAP fails to address the condition comprehensively, with the treatment targeting only a single pathogenesis. Herein, we report an innovative acid-responsive biomimetic nanozyme. This system features a hollow Prussian blue (PB) core, serving as an ROS scavenger encapsulated within a porous ZIF-8 shell, enabling the efficient delivery of celastrol that activates autophagic flux. Encased in a macrophage membrane, this system selectively targets inflamed pancreatic tissues and is readily internalized by pancreatic acinar cells. This dual-scavenging mechanism effectively attenuates inflammatory cytokine levels and restores mitochondrial homeostasis in three distinct SAP mouse models. Overall, this study presents a promising synergistic strategy for the dual scavenging of damaged mitochondria and ROS, offering a novel therapeutic approach to the treatment of SAP.

Severe acute pancreatitis (SAP) is a critical condition characterized by an imbalance between systemic inflammatory response syndrome (SIRS) and compensatory anti‐inflammatory response syndrome (CARS). Disruptions in intestinal microbiota exacerbate this imbalance; however, the mechanisms by which commensal bacteria regulate SAP‐induced SIRS and/or CARS remain unclear. This study reports that the abundance of the gut commensal Akkermansia is significantly reduced in fecal samples from patients with acute pancreatitis (AP) and is inversely associated with the severity of systemic inflammatory responses. Using Foxp3‐DTR and IL‐10‐KO mice, it is found that Akkermansia muciniphila and its derived protein Amuc_1409 can suppress SAP‐induced pancreatic and systemic inflammation by increasing peripheral regulatory T cells (Tregs) and enhancing the IL‐10 expression. Mechanistically, Amuc_1409 interacts with Ube2k to reduce the ubiquitination degradation of Foxp3, and it promotes the differentiation of Tregs and the production of IL‐10, effectively alleviating inflammation induced by SAP. These findings highlight A. muciniphila and its derivative Amuc_1409 as promising probiotic and biomolecule for managing acute pancreatitis and potentially other inflammatory conditions.