TGF-β1 induces PD-1 expression in macrophages through SMAD3/STAT3 cooperative signaling in chronic inflammation

Regulation of macrophage efferocytosis by the CLCF1/NF-κB pathway improves neurological and cognitive impairment following CO poisoning

Severe carbon monoxide (CO) poisoning can induce structural and functional damage to the nervous system, resulting in persistent cognitive impairments. Properly terminating inflammation caused by neuronal damage is essential for tissue repair. Macrophages clear cell corpses and fragments through efferocytosis and produce cytokines to coordinate the immune response, thus promoting neuronal repair and regeneration. However, within the microenvironment of the CO-affected nervous system, macrophage efferocytosis is disrupted. Our study found that macrophages regulate efferocytosis by releasing Cardiotrophin-like cytokine factor 1 (CLCF1), which modulates the NF-κB pathway in both macrophages and microglia, thereby controlling inflammation and promoting nervous system repair. Furthermore, efferocytosis regulates the secretion of cytokines such as TNF-α, IL-1β, and IL-10, promoting M2 polarization of macrophages, which aids in neuronal repair and regeneration. Regulating macrophage CLCF1 expression also leads to improvements in the memory, learning, and motor abilities of rats poisoned with CO.

Impact of fibrinogen-to-albumin ratio on the long-term prognosis of patients with advanced HER2-negative gastric cancer receiving immunochemotherapy

BACKGROUND

There is currently no effective targeted therapy for advanced HER2-negative gastric cancer (GC). While immunotherapy combined with chemotherapy is the first-line treatment for GC, patient survival outcomes remain highly heterogeneous, highlighting the urgent need for reliable predictive biomarkers. The fibrinogen-to-albumin ratio (FAR) integrates both inflammation (elevated fibrinogen levels) and nutritional status (reduced albumin levels). Although FAR has been associated with immunotherapy resistance in various solid tumors, its prognostic value in GC patients receiving immunochemotherapy remains unclear.

AIM

To assess the predictive value of the FAR in the long-term prognosis of advanced HER2-negative GC patients receiving sintilimab-based immunotherapy combined with chemotherapy.

METHODS

This retrospective study included 260 patients with unresectable or metastatic HER2-negative GC who received sintilimab plus chemotherapy from 2021 to 2024. Pre-treatment FAR values were calculated, and the optimal cutoff value was determined using receiver operating characteristic curve analysis. The association between the FAR and overall survival (OS) and progression-free survival (PFS) was analyzed using Kaplan-Meier survival curves and Cox proportional hazards models. Independent prognostic factors were identified by multivariate Cox regression analysis based on OS, and a nomogram model was constructed incorporating FAR. The concordance index (C-index) and calibration curves were used to assess the predictive performance and calibration of the model.

RESULTS

Patients with high FAR (≥ 0.08) had significantly shorter median PFS [7.80 months (6.40-8.30) vs 10.00 months (9.30-11.20), P < 0.001] and OS [14.20 months (12.20-16.60) vs 19.50 months (18.80-22.00), P < 0.001] compared to the group with low FAR (< 0.08). Moreover, the group with high FAR had a significantly lower objective response rate (10.22% vs 19.51%, P = 0.034) and disease control rate (34.31% vs 49.59%, P = 0.013). The incidence of adverse events did not significantly differ between the two groups (P > 0.05). Multivariate analysis confirmed the FAR as an independent prognostic factor for OS (HR = 2.33, 95%CI: 1.59-3.43, P < 0.001). The nomogram model, incorporating FAR, Eastern Cooperative Oncology Group performance status, programmed cell death ligand 1 expression, tumor stage, and body mass index, demonstrated strong predictive accuracy, with an internal validation C-index of 0.73 (95%CI: 0.66-0.79). The calibration curve showed a high consistency between predicted and actual survival rates.

CONCLUSION

Patients with low FAR had significantly better prognostic outcomes than those with high FAR when receiving immunochemotherapy. Thus, FAR may serve as a valuable prognostic biomarker for predicting survival outcomes in patients with advanced HER2-negative GC.

The Erk1/2-EGR1 signaling pathway is involved in lipopolysaccharide-induced transforming growth factor-beta 1 expression in mouse macrophages

Numerous studies have demonstrated that lipopolysaccharide (LPS) stimulates TGF-β1 expression. Although studies have implicated the NF-κB/METTL3/METTL14 transactivation/m6A-dependent and AMPK-dependent signaling pathways are engaged in this process in a variety of cell types, the underlying regulatory mechanism in murine macrophages is still not fully understood. To address this issue, in vitro studies were performed using the murine macrophage cell line, RAW264.7. The results showed that LPS challenge resulted in a significant increase in TGF-β1 expression at both mRNA and protein levels. Subsequent studies revealed that the MAPK (including p38, Erk1/2, and JNK) and NF-κB signaling pathways were activated in response to LPS stimulation, but only blocking the Erk1/2 singling pathway completely abolished LPS-induced TGF-β1 expression. Further studies revealed that the levels of a downstream regulator of the Erk1/2 pathway, EGR1, were significantly increased after LPS treatment, and its knockdown significantly reduced LPS-induced Tgf-β1 expression levels. Finally, dual luciferase reporter and ChIP-PCR assays confirmed that EGR1 is a key transcription factor in the regulation of Tgf-β1 expression by binding to its promoter region in response to LPS stimulation. In conclusion, we elucidated the molecular events by which LPS regulates TGF-β1 expression in murine macrophages through the Erk1/2-EGR1 signaling pathway. These findings provide a conceptually novel pathway for LPS-induced TGF-β1 expression beyond the known NF-κB/METTL3/METTL14 transactivation/m6A-dependent and AMPK-dependent signaling pathways.

Exosomes in bridging macrophage-fibroblast polarity and cancer stemness

Exosome roles in cellular cross-talking within tumor microenvironment (TME) is a critical event in tumorigenesis. Type 2 macrophages (M2), cancer-associated fibroblasts (CAFs) and cancer stem cells (CSCs) are the three most important cells in cancer progression and metastasis, and targeting their connectome route can be an effective anti-cancer strategy. Exosomes mediate bidirectional cross-talking between the three cell types in which exosomes secreted from CSCs promote polarization of M2 macrophages and CAFs, and that M2- and CAF-derived exosomes promote cancer stemness through activation of epithelial-mesenchymal transition (EMT)-related signaling including transforming growth factor (TGF)-β, WNT/β-catenin and epidermal growth factor (EGF). CSC-derived exosomal TGF-β is a key driver of CAF and M2 macrophage polarization, with the latter mediated through activation of signal transducer and activator of transcription 3 (STAT3). β-catenin activity also seems to take important role in exosomal cross-talk between CAFs and stemness state of cancer. Incubation of exosomes with inhibitors of signaling inter-connecting CSCs, M2 and CAFs is a key anti-cancer strategy and a promising supplementary to the routine immunotherapeutic approaches in cancer therapy.

PD-1 regulates the anti-tumor immune function of macrophages through JAK2-STAT3 signaling pathway in colorectal cancer tumor microenvironment

BACKGROUND

Tumor-associated macrophages (TAMs), as key immune components of the TME, play a pivotal role in tumor progression by fostering an immunosuppressive environment. Programmed death 1 (PD-1), a critical immune checkpoint molecule predominantly expressed on T cells, mediates immune suppression by binding to programmed death-ligand 1 (PD-L1) on tumor cells within the tumor microenvironment (TME). Emerging evidence reveals that TAMs also express PD-1, however, the expression and functional regulatory mechanisms of PD-1 on TAM remain poorly understood.

METHODS

In this study, we combined bulk RNA sequencing and single-cell RNA sequencing (scRNA-seq) data to investigate the association between PD-1 expression on macrophages and patient prognosis, while also uncovering the molecular mechanisms by which PD-1 regulates macrophage function. To further investigate the role of PD-1 in macrophage activity, we established a fluorescence-labeled tumor-bearing mouse model using CT26 cells, a murine colorectal cancer cell line, to evaluate the relationship between PD-1 expression on TAMs and their phagocytic activity as well as other functions. Additionally, to mimic the TME in vitro, we cultured bone marrow-derived macrophages (BMDMs) with CT26-conditioned medium (CT26-CM).

RESULTS

Our results suggest that PD-1 expression on TAMs drives macrophage polarization toward an M2-like phenotype, suppresses their phagocytic activity, inhibits the synthesis of interferon-γ (IFN-γ) signaling molecules, and ultimately promotes tumor progression. Mechanistically, we demonstrated that PD-1 regulates the synthesis of IFN-γ signaling molecules and the polarization of M2-type macrophages in BMDMs through the JAK2-STAT3 signaling pathway. Overall, our study demonstrates that PD-1 expression on TAMs facilitates the formation of an immunosuppressive microenvironment, ultimately accelerating tumor progression.

CLINICAL TRIAL NUMBER

Not applicable.

Molecular Mechanisms in Idiopathic Mitral Valve Chordae Tendineae Rupture: Insights from Transcriptome Analysis and Inflammation Evaluation

Objective

This study investigates the molecular mechanisms and hub genes in idiopathic rupture of mitral valve chordae tendineae (iRCT).

Methods

Histological changes were assessed via pathological staining, and transcriptome sequencing was performed on samples from 8 iRCT patients and 6 controls. Differentially expressed genes (DEGs), functional enrichment, PPI networks, and immune cell infiltration were analyzed. Hub gene expression was validated using RT-qPCR.

Results

iRCT samples exhibited cell proliferation, disorganized collagen fibers, and elastin fiber rupture. Immunohistochemical analysis further confirmed that activated fibroblasts, macrophages, dendritic cells, and T cells were increased in iRCT samples compared to normal samples. Additionally, iRCT samples exhibited an increased content of collagen fibers and elastin fibers. Transcriptome analysis identified 208 DEGs (109 upregulated, 99 downregulated) linked to inflammation, immune activation, and extracellular matrix remodeling.

Conclusion

iRCT involves ECM remodeling, inflammation, and immune dysregulation, with identified hub genes offering potential therapeutic targets.

Corticosterone effects induced by stress and immunity and inflammation: mechanisms of communication

The body instinctively responds to external stimuli by increasing energy metabolism and initiating immune responses upon receiving stress signals. Corticosterone (CORT), a glucocorticoid (GC) that regulates secretion along the hypothalamic-pituitary-adrenal (HPA) axis, mediates neurotransmission and humoral regulation. Due to the widespread expression of glucocorticoid receptors (GR), the effects of CORT are almost ubiquitous in various tissue cells. Therefore, on the one hand, CORT is a molecular signal that activates the body's immune system during stress and on the other hand, due to the chemical properties of GCs, the anti-inflammatory properties of CORT act as stabilizers to control the body's response to stress. Inflammation is a manifestation of immune activation. CORT plays dual roles in this process by both promoting inflammation and exerting anti-inflammatory effects in immune regulation. As a stress hormone, CORT levels fluctuate with the degree and duration of stress, determining its effects and the immune changes it induces. The immune system is essential for the body to resist diseases and maintain homeostasis, with immune imbalance being a key factor in the development of various diseases. Therefore, understanding the role of CORT and its mechanisms of action on immunity is crucial. This review addresses this important issue and summarizes the interactions between CORT and the immune system.

Euphorbia helioscopia L. inhibits lung tumorigenesis through alleviating exhausted T cell induced by chronic inflammation

ETHNOPHARMACOLOGICAL RELEVANCE

Euphorbia helioscopia L. (ZQ) is a very effective traditional Chinese medicine for treating pneumonia and lung cancer. However, the effects and mechanisms by which ZQ prevents lung tumorigenesis in the presence of chronic inflammation remain unexplored.

AIM

To examine the effects and mechanisms of ZQ in alleviating chronic inflammation-induced T cell exhaustion and inhibiting lung tumorigenesis.

METHODS

A mice model of lung tumorigenesis under chronic inflammation conditions was established by repeated administration of lipopolysaccharide (LPS) and exposure to the tobacco carcinogen nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Mice were treated with ZQ (0.9, 1.8, and 3.6 g/kg/day) for 25 weeks. Lung pathology and tumor incidence were assessed, and inflammatory cytokine levels in bronchoalveolar lavage fluid (BALF) and serum were measured. Additionally, the proportions of CD3+ T, CD4+ T, and CD8+ T cells and their inhibitory receptors expression were evaluated. In vitro, T cell exhaustion models were induced using inflammatory-conditioned media, followed by treatment with ZQ (0.5, 2, 8 μg/mL). T cell exhaustion markers and characteristics were analyzed, and molecular mechanisms were explored using RNA sequencing and Immunoblotting analysis.

RESULTS

In vivo, ZQ significantly reduced inflammatory infiltration and lung damage, tumor incidence, number, size, and lung and spleen indices in mice. It also markedly lowered the levels of pro-inflammatory cytokines and immunosuppressive cytokines in BALF and serum. Additionally, ZQ improved the proportions of CD3+ T, CD4+ T, and CD8+ T cells and significantly decreased the expression of inhibitory receptors on CD4+ T and CD8+ T cells in the lung tissues and spleen. In vitro, ZQ effectively alleviated T cell exhaustion induced by the inflammatory environment, marked by reduced expression of inhibitory receptors, increased cytokine secretion, improved proliferation, and enhanced tumoricidal activity. RNA sequencing revealed that ZQ significantly downregulated the JAK-STAT signaling and upregulated stemness-associated pathways. Immunoblotting results indicated that treatment with ZQ markedly reduced the phosphorylation of Signal transducer and activator of transcription 3 (STAT3) and increased the expression of T cell factor -1/7 (TCF1/7).

CONCLUSION

ZQ inhibits lung tumorigenesis in LPS/NNK-treated mice through alleviating exhausted T cells induced by chronic inflammation, which is attributed to the suppression of STAT3 activation and the maintenance of stemness characteristics in T cells. These findings provide experimental evidence for the potential use of ZQ in preventing and treating lung tumourigenesis in patients with chronic inflammation and the clinical management of lung cancer patients with concomitant chronic inflammation.