25-Hydroxycholesterol regulates lysosome AMP kinase activation and metabolic reprogramming to educate immunosuppressive macrophages

Smilax china L. Rhizome extract enhances anti-tumor immune responses by resetting M2-like macrophages and tumor-associated macrophages to M1-like via ERK1/2 signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Smilax china L. is a traditional Chinese herb. Smilax china L. Rhizome (SCR) have historically been used in ethnomedicine for their anti-inflammatory, anti-tumor, and immunomodulatory properties.

AIM OF THE STUDY

This study aimed to evaluate the anti-tumor efficacy of SCR in the MMTV-PyMT mouse mammary tumor model and elucidate its immunomodulatory mechanisms within the tumor microenvironment (TME).

MATERIALS AND METHODS

SCR was administered to MMTV-PyMT mice to assess its effects on tumor progression and metastasis. Immune cell profiling (M1/M2-like macrophages, CD8+ T cells) was conducted via flow cytometry. In vitro macrophage polarization assays under IL-4 stimulation and mechanistic studies (MAPK/ERK signaling) were performed using Western blot and pharmacological inhibitors. Diosgenin, a key SCR constituent, was identified and validated through phytochemical analysis and functional assays.

RESULTS

SCR treatment significantly slowed primary tumor growth and reduced lung metastases. SCR induces a shift in macrophage polarization from immunosuppressive M2-like to proinflammatory M1-like and promotes increased CD8+ T cell infiltration. In vitro, SCR inhibited IL-4-induced M2 polarization and suppressed ERK1/2 phosphorylation, a critical node in the MAPK pathway. Diosgenin was identified as a pivotal bioactive compound contributing to SCR's anti-tumor and immunomodulatory effects.

CONCLUSIONS

These findings provide a theoretical basis for the potential clinical application of SCR in cancer treatment, highlighting its critical role in remodeling the tumor immune microenvironment.

Sphingolipid synthesis in tumor-associated macrophages confers immunotherapy resistance in hepatocellular carcinoma

Dysregulated metabolism of immune cells in the tumor microenvironment leads to immune evasion and tumor progression. As a major cell component in the tumor, the metabolic reprogramming of tumor-associated macrophages (TAMs) creates an immunosuppressive microenvironment in hepatocellular carcinoma (HCC). Our study found that sphingolipid (particularly, sphingosine-1-phosphate or S1P) levels are a clinical indicator for prognosis and immunotherapy response in patients with HCC. S1P primarily derived from TAMs, where NIMA-related kinase 2 (NEK2) plays a key role in controlling the activity of serine palmitoyl-CoA transferase, a rate-limiting enzyme in S1P biosynthesis. The S1P produced by NEK2hi TAMs promotes hepatic tumor progression and confers immunotherapy resistance. Targeting S1P synthesis with a NEK2 inhibitor or S1P antagonist disrupted the immunosuppressive function of macrophages, shifted regulatory T cells (Tregs) to TH17 cells, and increased the number and activity of tumor-infiltrating T effectors, thereby enhancing antitumor efficacy in synergy with immune checkpoint blockade therapy.

Norcantharidin promotes M1 macrophage polarization and suppresses colorectal cancer growth

Colorectal cancer (CRC) is characterized by an immunosuppressive and inflammatory microenvironment, thus responds poorly to therapy. Previous studies show that norcantharidin (NCTD), a demethylated cantharidin (CTD) derived from Mylabris, exerts high efficacy in treating various cancers. In this study we investigated the antitumor effects of NCTD against CRC and the underlying mechanisms. Subcutaneous CRC models were established in balb/c mice using mouse colorectal cancer cell line CT26 and in balb/c nude mice using human colorectal cancer cell line HCT116. The mice were administered NCTD (2 or 4 mg·kg-1·d-1, i.p.) for 14 days. We showed that NCTD dose-dependently reduced the tumor growth in both the CRC models. Furthermore, NCTD markedly increased M1 macrophage infiltration in tumor tissue in both the CRC models. NCTD-induced macrophage M1 polarization was confirmed by flow cytometry and qPCR assays in both THP-1 cell-derived and RAW264.7 macrophage models in vitro. We demonstrated that NCTD (20, 40 μM) dose-dependently increased CSF2 secretion from CRC cells and macrophages, and suppressed the JAK2/STAT3 signaling pathway in CRC cells. Concurrently, NCTD (10-40 μM) dose-dependently inhibited CRC cell proliferation, invasion and migration in vitro. In conclusion, this study provides new evidence for the effects of NCTD against CRC and elucidates its antitumor mechanisms through remodeling the inflammatory microenvironment via CSF2-mediated macrophage M1 polarization and inhibiting JAK2/STAT3 phosphorylation in CRC cells.

Reprogramming and targeting of cholesterol metabolism in tumor-associated macrophages

Cholesterol, as a major component of cell membranes, is closely related to the metabolic regulation of cells and organisms; tumor-associated macrophages play an important push role in tumor progression. We know that tumor-associated macrophages are polarized from macrophages, and the abnormalities of cholesterol metabolism that may be induced during their polarization are worth discussing. This manuscript focuses on metabolic abnormalities in tumor-associated macrophages, and first provides a basic summary of the regulatory mechanisms of abnormal macrophage polarization. Subsequently, it comprehensively describes the features of abnormal glucose, lipid and cholesterol metabolism in TAMs as well as the different regulatory pathways. Then, the paper also discusses the link between abnormal cholesterol metabolism in TAMs and tumors, chronic diseases and aging. Finally, the paper summarizes cancer therapeutic strategies targeting cholesterol metabolism that are already in clinical trials, as well as nanomaterials capable of targeting cholesterol metabolism that are in the research stage, in the hope of providing value for the design of targeting materials. Overall, elucidating metabolic abnormalities in tumor-associated macrophages, particularly cholesterol metabolism, could provide assistance in tumor therapy and the design of targeted drugs.

IL-33-Induced TREM2+ Macrophages Promote Pathological New Bone Formation Through CREG1-IGF2R Axis in Ankylosing Spondylitis

Pathological new bone formation is the main cause of disability in ankylosing spondylitis (AS), and so far, it lacks a targeted therapy. Macrophages are central orchestrators of inflammation progression and tissue remodeling, but their contribution to pathological new bone formation has largely not been explored. Here, it is identified that TREM2+ macrophages predominated within the sites of new bone formation and adjacent to osteogenic precursor cells. In vivo, both depletion of macrophages and knockout of Trem2 significantly reduced pathological new bone formation in a collagen antibody-induced arthritis (CAIA) model. Specifically, TREM2+ macrophages promoted osteogenic differentiation of ligament-derived progenitor cells (LDPCs) by secreting CREG1, a secretory glycoprotein involved in cell differentiation and normal physiology. CREG1-IGF2R-PI3K-AKT signaling pathway is involved in TREM2+ macrophage-mediated pathological new bone formation. In addition, it is found that IL-33 promoted TREM2+ macrophage differentiation through phosphorylation of STAT6. Targeting the above signalings alleviated new bone formation in the CAIA model. The findings highlight the critical role of IL-33-induced TREM2+ macrophages in pathological new bone formation and provide potential therapeutic targets for halting spinal ankylosis in AS.

Construction of M2 macrophage-related gene signature for predicting prognosis and revealing different immunotherapy response in bladder cancer patients

BACKGROUND

Bladder cancer development is closely associated with the dynamic interaction and communication between M2 macrophages and tumor cells. However, specific biomarkers for targeting M2 macrophages in immunotherapy remain limited and require further investigation.

METHODS

In this study, we identified key co-expressed genes in M2 macrophages and developed gene signatures to predict prognosis and immunotherapy response in patients. Public database provided the bioinformatics data used in the analysis. We created and verified an M2 macrophage-related gene signature in these datasets using Lasso-Cox analysis.

RESULTS

The predictive value and immunological functions of our risk model were examined in bladder cancer patients, and 158 genes were found to be significantly positively correlated with M2 macrophages. Moreover, we identified two molecular subgroups of bladder cancer with markedly different immunological profiles and clinical prognoses. The five key risk genes identified in this model were validated, including CALU, ECM1, LRP1, CYTL1, and CCDC102B, demonstrating the model can accurately predict prognosis and identify unique responses to immunotherapy in patients with bladder cancer.

CONCLUSIONS

In summary, we constructed and validated a five-gene signature related to M2 macrophages, which shows strong potential for forecasting bladder cancer prognosis and immunotherapy response.

CH25H/25-HC promotes pulmonary fibrosis via AMPK/STAT6 pathway-dependent M2 macrophage polarization in COPD

OBJECTIVE

Chronic obstructive pulmonary disease (COPD) is intricately linked to pulmonary fibrosis, yet the underlying mechanisms remain unclear. This study investigates whether CH25H/25-hydroxycholesterol (25-HC) promotes pulmonary fibrosis in COPD by modulating AMPK/STAT6-dependent M2 macrophage polarization.

METHODS

Using GEO datasets and a cigarette smoke-induced COPD mouse model, we analyzed CH25H expression and fibrotic pathology. CH25H was silenced via adeno-associated virus (AAV)-delivered shRNA. Histopathology, flow cytometry, qPCR, and Western blotting assessed fibrosis, macrophage polarization (M1/M2), and AMPK/STAT6 pathway activity. Bone marrow-derived macrophages (BMDMs) were employed to validate polarization mechanisms. The role of the AMPK/STAT6 pathway was investigated using the specific activator.

RESULTS

Analysis of the GEO database and experimental verification showed significantly increased CH25H expression in both lung tissues and macrophages from COPD mice. CH25H knockdown alleviated alveolar damage, airway remodeling, and pulmonary fibrosis in COPD mice, evidenced by reduced expression of fibrosis-related proteins, improved lung function, and attenuated inflammatory responses. Moreover, CH25H knockdown inhibited M2 macrophage polarization and decreased the proportion of M2-type macrophages. Importantly, decreased levels of 25-HC following CH25H knockdown were asso ciated with suppressed activation of the AMPK/STAT6 pathway. Rescue experiments demonstrated that the protective effects of CH25H knockdown could be reversed by adding the AMPKα activator GSK621.

CONCLUSION

Our findings demonstrate that CH25H/25-HC exacerbates COPD-associated pulmonary fibrosis by promoting AMPK/STAT6-dependent M2 macrophage polarization. Targeting CH25H may represent a novel therapeutic strategy for mitigating fibrosis in COPD.

SNX10 Is Involved in Ovarian Cancer Cell Metastasis by Repolarizing Tumor-Associated Macrophages Through mTOR1/Lysosomes Pathway

Background: Tumor-associated macrophages (TAMs) are prevalent in advanced ovarian cancer tissues and ascites, significantly influencing disease prognosis. However, the mechanisms driving TAM polarization and their tumor-promoting effects remain poorly understood. Methods: The subcellular distribution of SNX10 in ovarian cancer tissues was analyzed using single-cell datasets (GSE147082, GSE58937). The Kaplan-Meier Plotter and GEPIA2 databases were used to evaluate SNX10's prognostic relevance. Lentivirus-mediated SNX10 overexpression in THP-1 cells was employed in tumor cell-macrophage co-culture experiments. Transwell assays and flow cytometry assessed SNX10's effects on ovarian cancer cell metastasis and cisplatin-induced apoptosis. RNA sequencing, Western blotting, lysosomal pH detection, lipid droplet staining, and RT-qPCR were performed to explore SNX10's molecular mechanisms in TAM polarization and immune modulation. Results: SNX10 was specifically expressed in TAMs, promoting their polarization into the M2 phenotype. This enhanced the migration and invasion of ovarian cancer cell lines A2780 and A2780/CP70 while reducing cisplatin-induced apoptosis. SNX10 decreased lipid droplet content, downregulated p-mTOR1, and impaired lysosomal function in TAMs. Additionally, SNX10 differentially modulated PD-L1 mRNA expression in platinum-sensitive and platinum-resistant ovarian cancer cells. Conclusions: SNX10 regulates the mTOR1/lysosome pathway in TAMs, influencing lipid metabolism and indirectly modulating ovarian cancer cell metastasis. It also alters PD-L1 mRNA expression, suggesting a role in shaping the tumor immune microenvironment.

Rehmanniae Radix Praeparata in Blood Deficiency Syndrome: UPLC-Q-TOF-MS Profiling, Network Pharmacology, and PI3K-AKT Activation

This study investigated the therapeutic mechanism of Rehmanniae Radix Praeparata (RRP) in treating blood deficiency syndrome (BDS) through integrated chemical analysis and pharmacological validation. UPLC-Q-TOF-MS identified chemical components of Rehmanniae Radix (RR) and RRP, with network pharmacology analysis suggesting AKT1 and NOS3 in the PI3K-AKT pathway as potential therapeutic targets. Pharmacodynamic evaluations using ELISA, hematological analysis, histopathology, and immunohistochemistry demonstrated RRP's efficacy in improving hematological parameters, energy metabolism, and organ pathology in BDS mice. Experimental validation via RT-qPCR and Western blot confirmed significant upregulation of AKT1 and NOS3 mRNA and protein expression following RRP treatment. The findings indicate that RRP alleviates BDS by activating the PI3K-Akt signaling pathway to modulate AKT1 and NOS3 expression, providing mechanistic insights into its therapeutic actions.

Acetyl-CoA synthetase 2 alleviates brain injury following cardiac arrest by promoting autophagy in brain microvascular endothelial cells

INTRODUCTION

Brain injury is a common sequela following cardiac arrest (CA), with up to 70% of hospitalized patients dying from it. Brain microvascular endothelial cells (BMVECs) play a crucial role in post-cardiac arrest brain injury (PCABI). However, the effects and mechanisms of targeting BMVEC energy metabolism to mitigate brain injury remain unclear.

METHODS

We established a mouse model of cardiac arrest by injecting potassium chloride into the right internal jugular vein. Mass spectrometry detected targeted changes in short-chain fatty acids and energy metabolism metabolites in the CA/CPR group compared to the sham group. Mice with overexpressed ACSS2 in BMVECs were created using an AAV-BR1 vector, and ACSS2 knockout mice were generated using the CRE-LOXP system. The oxygen glucose deprivation/re-oxygenation (OGD/R) model was established to investigate the role and mechanisms of ACSS2 in endothelial cells in vitro.

RESULTS

Metabolomics analysis revealed disrupted cerebral energy metabolism post-CA/CPR, with decreased acetyl-CoA and amino acids. Overexpression of ACSS2 in BMVECs increased acetyl-CoA levels and improved neurological function. Vascular endothelial cell-specific ACSS2 knockout mice exhibited reduced aortic sprouting in vitro. Overexpression of ACSS2 improved endothelial dysfunction following oxygen glucose deprivation/re-oxygenation (OGD/R) and influenced autophagy by interacting with transcription factor EB (TFEB) and modulating the AMP-activated protein kinase α (AMPKα) pathway.

CONCLUSION

Our study shows that ACSS2 modulates the biological functions of BMVECs by promoting autophagy. Enhancing energy metabolism via ACSS2 may target PCABI treatment development.

Immunogenic Cell Death and Metabolic Reprogramming in Cancer: Mechanisms, Synergies, and Innovative Therapeutic Strategies

Immunogenic cell death (ICD) is a promising cancer therapy where dying tumor cells release damage-associated molecular patterns (DAMPs) to activate immune responses. Recent research highlights the critical role of metabolic reprogramming in tumor cells, including the Warburg effect, oxidative stress, and lipid metabolism, in modulating ICD and shaping the immune microenvironment. These metabolic changes enhance immune activation, making tumors more susceptible to immune surveillance. This review explores the molecular mechanisms linking ICD and metabolism, including mitochondrial oxidative stress, endoplasmic reticulum (ER) stress, and ferroptosis. It also discusses innovative therapeutic strategies, such as personalized combination therapies, metabolic inhibitors, and targeted delivery systems, to improve ICD efficacy. The future of cancer immunotherapy lies in integrating metabolic reprogramming and immune activation to overcome tumor immune evasion, with multi-omics approaches and microbiome modulation offering new avenues for enhanced treatment outcomes.

The transition between M1 and M2 macrophage phenotypes is associated with the disease status following CD19 CAR-T therapy for B cell lymphoma/leukemia

Although anti-CD19 chimeric antigen receptor (CAR-T) cells demonstrate high response rates in relapsed/refractory B-cell lymphomas, a considerable proportion of patients eventually encounter disease progression or relapse. The short-term and long-term outcomes of CAR-T treatment are intricately linked to the tumor microenvironment (TME), wherein macrophages with polarized characteristics can exhibit either anti-tumorigenic or pro-tumorigenic roles. Despite evidence implicating the crucial involvement of macrophages in CAR-T cell-treated lymphoma, their dynamic distribution and immune function related to lymphoma progression remain poorly understood. Immunocompetent mice were utilized to establish syngeneic A20 lymphoma/leukemia models. The distribution and polarization of macrophages were detected using immunohistochemistry (IHC) and flow cytometry techniques. We observed that CD19 CAR-T therapy exhibited significant efficacy in protecting mice against lymphoma, leading to increased infiltration of macrophages into the tumor tissue. Notably, during remission stages, M1-like macrophages (CD11b+F4/80+C206-CD80+) were predominant, whereas in relapsed mice, there was a shift towards M2-like phenotypes (CD11b+F4/80+C206+CD80+). The transition from remissive to relapsed status was accompanied by a reduction in the M1/M2 ratio and a decrease in pro-inflammatory cytokines. Furthermore, quantitative real-time polymerase chain reaction (qRT-PCR) analysis confirmed differential expression levels of CD206 and CD163 between remissive and relapsed mice, while signaling pathways involving PI3K and STAT3 may contribute to the skewing towards M2 polarization. In summary, our findings highlight the dynamic transformation of macrophage polarization during different stages of lymphoma progression and underscore its potential implications for immunotherapeutic interventions.

Cholesterol effects on the tumor immune microenvironment: from fundamental concepts to mechanisms and implications

In many cancers, the tumor microenvironment is enriched with cholesterol due to increased biosynthesis and uptake by cancer cells, resulting in the accumulation of cholesterol, cholesterol esters, oxysterols and other metabolites with various functions. These molecules serve as structural components, energy sources and intracellular signaling mediators, while their toxic by-products are secreted to suppress anti-tumor immune activity and prevent lipid peroxidation that could induce cancer cell apoptosis. Immune cells in the tumor microenvironment also contribute to cholesterol dynamics. Tumor-associated macrophages (TAMs) release cholesterol to support tumor cell metabolism, while myeloid-derived suppressor cells (MDSCs) also release cholesterol and consume essential metabolites such as L-arginine, which impairs T-cell proliferation and activation. Elevated cholesterol in dendritic cells impairs migration and tumor antigen presentation and, in lymphocytes, favors the development of a regulatory T cells (Treg) phenotype and inhibits the release of antitumor cytokines, further weakening the immune response. These findings suggest that targeting cholesterol metabolism is a promising strategy for cancer treatment, improving the efficacy of immune checkpoint blockade (ICB) therapies. In this manuscript, the molecular mechanisms underlying the effects of cholesterol on the tumor immune landscape are reviewed and the potential of cholesterol-lowering drugs to enhance antitumor immune responses is explored.

Cholesterol metabolism in tumor immunity: Mechanisms and therapeutic opportunities for cancer

Cholesterol is an essential component of the cell membrane which plays a critical role in the survival of immune and tumor cells. Reprogramming of cholesterol metabolism in both tumor cells and immune cells can impact tumor progression and anti-tumor immune responses. Strategies aimed at modulating cholesterol metabolism have been demonstrated to be effective in hindering tumor growth and boosting anti-tumor immune functions. This review provides a thorough analysis of intracellular cholesterol homeostasis regulation in cells, focusing on key genes and signaling pathways. It particularly emphasizes the regulatory mechanisms and importance of the cholesterol presence state (esterified/free), levels of cholesterol, and its metabolites in immune and tumor cells. Additionally, the review thoroughly explores how cholesterol metabolism and sources (endogenous/exogenous) in the tumor microenvironment (TME) contribute to the interplay among tumor cells, immune suppressor cells, and immune effector cells, promoting cancer progression and immune evasion. It also delves into current insights on the influence of cholesterol metabolites and related drugs in regulating tumor development or immunotherapy. Finally, it presents an overview of recent advancements in clinical and preclinical trials investigating the efficacy of targeted cholesterol metabolism treatments and combination therapies in cancer management, while proposing potential future research directions in tumor immunity. This review is poised to offer fresh perspectives and avenues for examining the potential of cancer immunotherapy centered on cholesterol metabolism regulation.

Myeloid cells: key players in tumor microenvironments

Cancer is the result of evolving crosstalk between neoplastic cell and its immune microenvironment. In recent years, immune therapeutics targeting T lymphocytes, such as immune checkpoint blockade (ICB) and CAR-T, have made significant progress in cancer treatment and validated targeting immune cells as a promising approach to fight human cancers. However, responsiveness to the current immune therapeutic agents is limited to only a small proportion of solid cancer patients. As major components of most solid tumors, myeloid cells played critical roles in regulating the initiation and sustentation of adaptive immunity, thus determining tumor progression as well as therapeutic responses. In this review, we discuss emerging data on the diverse functions of myeloid cells in tumor progression through their direct effects or interactions with other immune cells. We explain how different metabolic reprogramming impacts the characteristics and functions of tumor myeloid cells, and discuss recent progress in revealing different mechanisms-chemotaxis, proliferation, survival, and alternative sources-involved in the infiltration and accumulation of myeloid cells within tumors. Further understanding of the function and regulation of myeloid cells is important for the development of novel strategies for therapeutic exploitation in cancer.

CaMKK2 Regulates Macrophage Polarization Induced by Matrix Stiffness: Implications for Shaping the Immune Response in Stiffened Tissues

Macrophages are essential for immune responses and maintaining tissue homeostasis, exhibiting a wide range of phenotypes depending on their microenvironment. The extracellular matrix (ECM) is a vital component that provides structural support and organization to tissues, with matrix stiffness acting as a key regulator of macrophage behavior. Using physiologically relevant 3D stiffening hydrogel models, it is found that increased matrix stiffness alone promoted macrophage polarization toward a pro-regenerative phenotype, mimicking the effect of interleukin-4(IL-4) in softer matrices. Blocking Calcium/calmodulin-dependent kinase kinase 2 (CaMKK2) selectively inhibited stiffness-induced macrophage polarization without affecting IL-4-driven pro-regenerative pathways. In functional studies, CaMKK2 deletion prevented M2-like/pro-tumoral polarization caused by matrix stiffening, which in turn hindered tumor growth. In a murine wound healing model, loss of CaMKK2 impaired matrix stiffness-mediated macrophage accumulation, ultimately disrupting vascularization. These findings highlight the critical role of CaMKK2 in the macrophage mechanosensitive fate determination and gene expression program, positioning this kinase as a promising therapeutic target to selectively modulate macrophage responses in pathologically stiff tissues.

Metabolites and metabolic pathway reactions links to sensitization of immunotherapy in pan-cancer

Metabolic features are crucial in tumor immune interactions, but their relationship with antitumor immune responses is not yet fully understood. This study used Mendelian randomization analysis to identify the causal relationships between blood metabolites and immune cells and to evaluate the effects of metabolic pathways and reactions on antitumor immune responses in various cancers. Levels of 156 metabolites exhibited significant associations with selected immune cells. Metabolic enrichment analysis indicated laurate, propionyl-carnitine, carnitine and l-acetylcarnitine are enriched in fatty acid (FA) metabolism pathways. These enriched pathways are significantly correlated to CD8+ T cell function signatures in tumor environment and favor better prognostic outcomes. Metabolic reactions contributing to better immunotherapy responses were identified and used to establish the immuno-metabolic reaction score (IMRS). IMRS were significantly correlated to CD8+ T cell infiltration levels and CD8+ T cell signature scores in either 10× Visium spatial transcriptomic or RNA-seq samples. Finally, IMRS could significantly predict favorable survival outcomes in different cancer patients treated with immunotherapy. Our study revealed a link between certain metabolites and their related metabolic pathways to tumor immune landscape and immune functions. These results could promote the accurate stratification of patients before treatment and improve the efficacy of immunotherapy.

Engineered MXene Biomaterials for Regenerative Medicine

MXene-based materials have attracted significant interest due to their distinct physical and chemical properties, which are relevant to fields such as energy storage, environmental science, and biomedicine. MXene has shown potential in the area of tissue regenerative medicine. However, research on its applications in tissue regeneration is still in its early stages, with a notable absence of comprehensive reviews. This review begins with a detailed description of the intrinsic properties of MXene, followed by a discussion of the various nanostructures that MXene can form, spanning from 0 to 3 dimensions. The focus then shifts to the applications of MXene-based biomaterials in tissue engineering, particularly in immunomodulation, wound healing, bone regeneration, and nerve regeneration. MXene's physicochemical properties, including conductivity, photothermal characteristics, and antibacterial properties, facilitate interactions with different cell types, influencing biological processes. These interactions highlight its potential in modulating cellular functions essential for tissue regeneration. Although the research on MXene in tissue regeneration is still developing, its versatile structural and physicochemical attributes suggest its potential role in advancing regenerative medicine.

Tissue macrophages: origin, heterogenity, biological functions, diseases and therapeutic targets

Macrophages are immune cells belonging to the mononuclear phagocyte system. They play crucial roles in immune defense, surveillance, and homeostasis. This review systematically discusses the types of hematopoietic progenitors that give rise to macrophages, including primitive hematopoietic progenitors, erythro-myeloid progenitors, and hematopoietic stem cells. These progenitors have distinct genetic backgrounds and developmental processes. Accordingly, macrophages exhibit complex and diverse functions in the body, including phagocytosis and clearance of cellular debris, antigen presentation, and immune response, regulation of inflammation and cytokine production, tissue remodeling and repair, and multi-level regulatory signaling pathways/crosstalk involved in homeostasis and physiology. Besides, tumor-associated macrophages are a key component of the TME, exhibiting both anti-tumor and pro-tumor properties. Furthermore, the functional status of macrophages is closely linked to the development of various diseases, including cancer, autoimmune disorders, cardiovascular disease, neurodegenerative diseases, metabolic conditions, and trauma. Targeting macrophages has emerged as a promising therapeutic strategy in these contexts. Clinical trials of macrophage-based targeted drugs, macrophage-based immunotherapies, and nanoparticle-based therapy were comprehensively summarized. Potential challenges and future directions in targeting macrophages have also been discussed. Overall, our review highlights the significance of this versatile immune cell in human health and disease, which is expected to inform future research and clinical practice.

Metabolomic analysis of rat arterial serum under hypobaric hypoxia: Adaptive regulation of physiological systems by metabolic reprogramming

Objective

To investigate the associations between metabolic changes and functions, including energy metabolism, immune response, and redox balance, under short-term hypobaric hypoxia exposure. Non-targeted metabolomics and bioinformatics analysis were applied to explore the adaptive mechanisms of organisms in hypobaric hypoxia.

Methods

Healthy adult male Sprague-Dawley rats were placed in environments simulating altitudes of 6500 m (HC group) and 1588 m (Control group). After 14 days, arterial serum samples were analyzed using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS). Significant metabolites (P < 0.05, VIP >1) were identified, and KEGG enrichment analysis was conducted. Differential metabolites were globally analyzed with MetaboAnalyst 5.0.

Results

A total of 117 significantly altered metabolites were identified. In the HC group, 84 metabolites significantly increased, while 33 metabolites significantly decreased compared to the Control group. KEGG enrichment analysis revealed significant metabolic pathways, including the PPAR signaling pathway, bile secretion, arginine biosynthesis, alcoholism, and cholesterol metabolism (P < 0.05). Global analysis indicated that these differential metabolites were involved in various pathways, such as energy metabolism, amino acid metabolism, nucleotide metabolism, lipid metabolism, vitamin and cofactor metabolism, steroid metabolism, neurotransmitter metabolism, and heme metabolism, all of which play crucial roles in multiple biological processes.

Conclusion

Short-term hypobaric hypoxia exposure significantly altered the metabolite profiles in the arterial serum samples of rats, revealing adaptive metabolic reprogramming in energy metabolism, redox balance, immune function, endocrine regulation, and neurological systems.

Anti-Tumor Strategies Targeting Nutritional Deprivation: Challenges and Opportunities

Higher and richer nutrient requirements are typical features that distinguish tumor cells from AU: cells, ensuring adequate substrates and energy sources for tumor cell proliferation and migration. Therefore, nutrient deprivation strategies based on targeted technologies can induce impaired cell viability in tumor cells, which are more sensitive than normal cells. In this review, nutrients that are required by tumor cells and related metabolic pathways are introduced, and anti-tumor strategies developed to target nutrient deprivation are described. In addition to tumor cells, the nutritional and metabolic characteristics of other cells in the tumor microenvironment (including macrophages, neutrophils, natural killer cells, T cells, and cancer-associated fibroblasts) and related new anti-tumor strategies are also summarized. In conclusion, recent advances in anti-tumor strategies targeting nutrient blockade are reviewed, and the challenges and prospects of these anti-tumor strategies are discussed, which are of theoretical significance for optimizing the clinical application of tumor nutrition deprivation strategies.

Effects of natural products on macrophage immunometabolism: A new frontier in the treatment of metabolic diseases

Immunometabolic variations in macrophages critically influence their differentiation into pro-inflammatory or anti-inflammatory phenotypes, thereby contributing to immune homeostasis, defense against infection, and tissue repair. Dysregulation of macrophage immunometabolism has been closely implicated in several metabolic diseases, including obesity, type 2 diabetes mellitus (T2DM), non-alcoholic fatty liver disease (NAFLD), hypertension, atherosclerosis, and gout, which positions macrophages as potential therapeutic targets. Recently, several natural products that target macrophage metabolic pathways have shown significant efficacy in managing metabolic diseases; however, a systematic review of these findings has yet to be conducted. This study consolidates natural products with immunoregulatory properties, including flavonoids, phenols, terpenoids, and naphthoquinones, which can alleviate chronic inflammation associated with metabolic disorders by modulating macrophage metabolic pathways, such as aerobic glycolysis, oxidative phosphorylation (OXPHOS), and fatty acid oxidation (FAO). This review aims to elucidate the metabolic regulation of the immune system, analyze metabolic alterations in macrophage associated with metabolic diseases, and summarize the beneficial roles of natural products in immunometabolism, providing novel insights for the prevention and therapeutic management of metabolic diseases.

25-Hydroxycholesterol modulates microglial function and exacerbates Alzheimer's disease pathology: mechanistic insights and therapeutic potential of cholesterol esterification inhibition

This study investigates the role of 25-hydroxycholesterol (25HC), a metabolite produced by cholesterol hydroxylase encoded by the Ch25h gene, in modulating microglial function and its potential implications in Alzheimer's disease (AD) pathology. We demonstrated that 25HC impairs microglial surveillance, reduces phagocytic capacity, and increases the production of pro-inflammatory cytokines. In vivo two-photon microscopy revealed that 25HC administration diminishes microglial response to brain lesions, while flow cytometry confirmed reduced phagocytosis in both in vivo and in vitro models. Additionally, amyloid-beta (Aβ) was shown to upregulate Ch25h expression and elevate 25HC levels in microglia, exacerbating these functional impairments. Mechanistically, 25HC was found to enhance cholesterol esterification, disrupt cell membrane dynamics, and further reduce microglial mobility and phagocytosis. Treatment with Avasimibe, a cholesterol esterification inhibitor, restored membrane dynamics and microglial function, leading to attenuated AD pathology in a 5XFAD mouse model. These findings suggest that 25HC-induced changes in microglial function contribute to AD progression, and targeting cholesterol metabolism could offer therapeutic potential.

The role of macrophages in liver metastasis: mechanisms and therapeutic prospects

Metastasis is a hallmark of advanced cancer, and the liver is a common site for secondary metastasis of many tumor cells, including colorectal, pancreatic, gastric, and prostate cancers. Macrophages in the tumor microenvironment (TME) promote tumor cell metastasis through various mechanisms, including angiogenesis and immunosuppression, and play a unique role in the development of liver metastasis. Macrophages are affected by a variety of factors. Under conditions of hypoxia and increased acidity in the TME, more factors are now found to promote the polarization of macrophages to the M2 type, including exosomes and amino acids. M2-type macrophages promote tumor cell angiogenesis through a variety of mechanisms, including the secretion of factors such as VEGF, IL-1β, and TGF-β1. M2-type macrophages are subjected to multiple regulatory mechanisms. They also interact with various cells within the tumor microenvironment to co-regulate certain conditions, including the creation of an immunosuppressive microenvironment. This interaction promotes tumor cell metastasis, drug resistance, and immune escape. Based on the advent of single-cell sequencing technology, further insights into macrophage subpopulations in the tumor microenvironment may help in exploring new therapeutic targets in the future. In this paper, we will focus on how macrophages affect the TME, how tumor cells and macrophages as well as other immune cells interact with each other, and further investigate the mechanisms involved in liver metastasis of tumor cells and their potential as therapeutic targets.

AMPK: An energy sensor for non-small cell lung cancer progression and treatment

Lung cancer (LC) is the leading cause of cancer-related morbidity and mortality in China, with non-small cell lung cancer (NSCLC) accounting for 85 % of the overall lung cancer cases. AMP-activated protein kinase (AMPK) is a key regulator of energy balance and homeostasis, and its dysregulation is a common feature in various malignancies, particularly in NSCLC with mutations in Liver kinase B1 (LKB1). Studies have shown that the AMPK signalling pathway has a dual role in NSCLC progression, both inhibiting and promoting the progression of malignant tumours. Therefore, drugs targeting the AMPK signalling pathway may hold significant promise for therapeutic application in NSCLC. This review aims to examine the manifestations and mechanisms by which AMPK and its associated signalling molecules influence NSCLC progression and treatment. Firstly, we discuss the critical importance of AMPK within the mutational context of NSCLC. Secondly, we summarise the drugs and related substances that modulate the AMPK signalling pathway in NSCLC and evaluate the evidence from preclinical studies on combination AMPK-targeted therapies to address the issue of drug resistance in NSCLC under current clinical treatments. In summary, this paper highlights the critical importance of developing AMPK-targeted drugs to enhance therapeutic efficacy in NSCLC, as well as the potential for applying these drugs in clinical therapy to overcome drug resistance.

Lactylation: The metabolic accomplice shaping cancer's response to radiotherapy and immunotherapy

Protein lactylation, an emerging post-translational modification, is providing new insights into tumor biology and challenging our current understanding of cancer mechanisms. Our review illuminates the intricate roles of lactylation in carcinogenesis, tumor progression, and therapeutic responses, positioning it as a critical linchpin connecting metabolic reprogramming, epigenetic modulation, and treatment outcomes. We provide an in-depth analysis of lactylation's molecular mechanisms and its far-reaching impact on cell cycle regulation, immune evasion strategies, and therapeutic resistance within the complex tumor microenvironment. Notably, this review dissects the paradoxical nature of lactylation in cancer immunotherapy and radiotherapy. While heightened lactylation can foster immune suppression and radioresistance, strategically targeting lactylation cascades opens innovative avenues for amplifying the efficacy of current treatment paradigms. We critically evaluate lactylation's potential as a robust diagnostic and prognostic biomarker and explore frontier therapeutic approaches targeting lactylation. The synergistic integration of multi-omics data and artificial intelligence in lactylation research is catalyzing significant strides towards personalized cancer management. This review not only consolidates current knowledge but also charts a course for future investigations. Key research imperatives include deciphering tumor-specific lactylation signatures, optimizing synergistic strategies combining lactylation modulation with immune checkpoint inhibitors and radiotherapy, and comprehensively assessing the long-term physiological implications of lactylation intervention. As our understanding of lactylation's pivotal role in tumor biology continues to evolve, this burgeoning field promises to usher in transformative advancements in cancer diagnosis, treatment modalitie.

Lymphatic-derived oxysterols promote anti-tumor immunity and response to immunotherapy in melanoma

In melanoma, lymphangiogenesis correlates with metastasis and poor prognosis and promotes immunosuppression. However, it also potentiates immunotherapy by supporting immune cell trafficking. We show in a lymphangiogenic murine melanoma that lymphatic endothelial cells (LECs) upregulate the enzyme Ch25h, which catalyzes the formation of 25-hydroxycholesterol (25-HC) from cholesterol and plays important roles in lipid metabolism, gene regulation, and immune activation. We identify a role for LECs as a source of extracellular 25-HC in tumors inhibiting PPAR-γ in intra-tumoral macrophages and monocytes, preventing their immunosuppressive function and instead promoting their conversion into proinflammatory myeloid cells that support effector T cell functions. In human melanoma, LECs also upregulate Ch25h, and its expression correlates with the lymphatic vessel signature, infiltration of pro-inflammatory macrophages, better patient survival, and better response to immunotherapy. We identify here in mechanistic detail an important LEC function that supports anti-tumor immunity, which can be therapeutically exploited in combination with immunotherapy.

Nanomaterial-enabled metabolic reprogramming strategies for boosting antitumor immunity

Immunotherapy has become a crucial strategy in cancer treatment, but its effectiveness is often constrained. Most cancer immunotherapies focus on stimulating T-cell-mediated immunity by driving the cancer-immunity cycle, which includes tumor antigen release, antigen presentation, T cell activation, infiltration, and tumor cell killing. However, metabolism reprogramming in the tumor microenvironment (TME) supports the viability of cancer cells and inhibits the function of immune cells within this cycle, presenting clinical challenges. The distinct metabolic needs of tumor cells and immune cells require precise and selective metabolic interventions to maximize therapeutic outcomes while minimizing adverse effects. Recent advances in nanotherapeutics offer a promising approach to target tumor metabolism reprogramming and enhance the cancer-immunity cycle through tailored metabolic modulation. In this review, we explore cutting-edge nanomaterial strategies for modulating tumor metabolism to improve therapeutic outcomes. We review the design principles of nanoplatforms for immunometabolic modulation, key metabolic pathways and their regulation, recent advances in targeting these pathways for the cancer-immunity cycle enhancement, and future prospects for next-generation metabolic nanomodulators in cancer immunotherapy. We expect that emerging immunometabolic modulatory nanotechnology will establish a new frontier in cancer immunotherapy in the near future.

Emerging role of metabolic reprogramming in the immune microenvironment and immunotherapy of thyroid cancer

The metabolic reprogramming of cancer cells is a hallmark of many malignancies. To meet the energy acquisition needs of tumor cells for rapid proliferation, tumor cells reprogram their nutrient metabolism, which is caused by the abnormal expression of transcription factors and signaling molecules related to energy metabolic pathways as well as the upregulation and downregulation of abnormal metabolic enzymes, receptors, and mediators. Thyroid cancer (TC) is the most common endocrine tumor, and immunotherapy has become the mainstream choice for clinical benefit after the failure of surgical, endocrine, and radioiodine therapies. TC change the tumor microenvironment (TME) through nutrient competition and metabolites, causing metabolic reprogramming of immune cells, profoundly changing immune cell function, and promoting immune evasion of tumor cells. A deeper understanding of how metabolic reprogramming alters the TME and controls immune cell fate and function will help improve the effectiveness of TC immunotherapy and patient outcomes. This paper aims to elucidate the metabolic communication that occurs between immune cells around TC and discusses how metabolic reprogramming in TC affects the immune microenvironment and the effectiveness of anti-cancer immunotherapy. Finally, targeting key metabolic checkpoints during metabolic reprogramming, combined with immunotherapy, is a promising strategy.

Unraveling the AMPK-SIRT1-FOXO Pathway: The In-Depth Analysis and Breakthrough Prospects of Oxidative Stress-Induced Diseases

Oxidative stress (OS) refers to the production of a substantial amount of reactive oxygen species (ROS), leading to cellular and organ damage. This imbalance between oxidant and antioxidant activity contributes to various diseases, including cancer, cardiovascular disease, diabetes, and neurodegenerative conditions. The body's antioxidant system, mediated by various signaling pathways, includes the AMPK-SIRT1-FOXO pathway. In oxidative stress conditions, AMPK, an energy sensor, activates SIRT1, which in turn stimulates the FOXO transcription factor. This cascade enhances mitochondrial function, reduces mitochondrial damage, and mitigates OS-induced cellular injury. This review provides a comprehensive analysis of the biological roles, regulatory mechanisms, and functions of the AMPK-SIRT1-FOXO pathway in diseases influenced by OS, offering new insights and methods for understanding OS pathogenesis and its therapeutic approaches.

Crosstalk between ferroptosis and autophagy: broaden horizons of cancer therapy

Ferroptosis and autophagy are two main forms of regulated cell death (RCD). Ferroptosis is a newly identified RCD driven by iron accumulation and lipid peroxidation. Autophagy is a self-degradation system through membrane rearrangement. Autophagy regulates the metabolic balance between synthesis, degradation and reutilization of cellular substances to maintain intracellular homeostasis. Numerous studies have demonstrated that both ferroptosis and autophagy play important roles in cancer pathogenesis and cancer therapy. We also found that there are intricate connections between ferroptosis and autophagy. In this article, we tried to clarify how different kinds of autophagy participate in the process of ferroptosis and sort out the common regulatory pathways between ferroptosis and autophagy in cancer. By exploring the complex crosstalk between ferroptosis and autophagy, we hope to broaden horizons of cancer therapy.

Oxysterols in tumor immune microenvironment (TIME)

Oxysterols are compounds generated through oxidative reactions involving cholesterol and other steroid molecules. They play a crucial role in the tumor immune microenvironment by interacting with molecules such as the cell membrane receptor EBI2 and nuclear receptors like LXR and PXR. This interaction regulates immune cell signaling pathways, affecting proliferation, apoptosis, migration, and invasion in tumor-related processes. Activating these receptors alters the function and behavior of immune cells-such as macrophages, T cells, and dendritic cells-within the tumor microenvironment, thus promoting or inhibiting tumor development. Certain oxidized steroids can increase both the number and activation of infiltrating T cells, synergizing with anti-PD-1 to enhance anti-tumor efficacy. An in-depth study of the biological mechanisms of oxidized sterols will not only enhance our understanding of the complexity of the tumor immune microenvironment but may also reveal new therapeutic targets, providing innovative strategies for tumor immunotherapy.

Bioorthogonal Engineering of Bacterial Outer Membrane Vesicles for NIR-II Fluorescence Imaging-Guided Synergistic Enhanced Immunotherapy

The efficacy of immunotherapy in treating triple-negative breast cancer (TNBC) has been restricted due to its low immunogenicity and suppressive immune microenvironment. Bacterial outer membrane vesicles (OMVs) have emerged as innovative immunotherapeutic agents in antitumor therapy by stimulating the innate immune system, but intricate modifications and undesirable multiple dose administration severely hinder their utility. Herein, a two-step bacterial metabolic labeling technique was utilized for the bioorthogonal engineering of OMVs. At first, d-propargylglycine (DPG, an alkyne-containing d-amino acid) was introduced into the incubation process of probiotic Escherichia coli 1917 (Ecn) to produce DPG-functionalized OMVs, which were subsequently conjugated with azide-functionalized new indocyanine green (IR820) to yield OMV-DPG-IR820. The combination of phototherapy and immunostimulation of OMV-DPG-IR820 effectively arouses adaptive immune responses, causing maturation of dendritic cells, infiltration of T cells, repolarization of the M2 macrophage to the M1 macrophage, and upregulation of inflammatory factors. Remarkably, OMV-DPG-IR820 demonstrated tumor-targeting capabilities with guidance provided by near-infrared II (NIR-II) fluorescence imaging, leading to remarkable inhibition on both primary and distant tumors and preventing metastasis without causing noticeable adverse reactions. This study elucidates a sophisticated bioorthogonal engineering strategy for the design and production of functionalized OMVs and provides novel perspectives on the microbiome-mediated reversal of TNBC through a precise and efficient immunotherapy.

Myeloid effector cells in cancer

The role of myeloid cells in tumor immunity is multifaceted. While dendritic cells support T cell-mediated tumor control, the highly heterogenous populations of macrophages, neutrophils, and immature myeloid cells were generally considered immunosuppressive. This view has led to effective therapies reinvigorating tumor-reactive T cells; however, targeting the immunosuppressive effects of macrophages and neutrophils to boost the cancer immunity cycle was clinically less successful. Recent studies interrogating the role of immune cells in the context of successful immunotherapy affirm the key role of T cells, but simultaneously challenge the idea that the cytotoxic function of T cells is the main contributor to therapy-driven tumor regression. Rather, therapy-activated intra-tumoral T cells recruit and activate or reprogram several myeloid effector cell types, the presence of which is necessary for tumor rejection. Here, we reappreciate the key role of myeloid effector cells in tumor rejection as this may help to shape future successful immunotherapies.

Multi-Omics Profiling and Experimental Verification of Lysosomes-Related Genes in Hepatocellular Carcinoma

Lysosomes play a crucial role in regulating the growth, invasion and metastasis of different tumour types. However, the specific function of lysosomes in hepatocellular carcinoma (HCC) remains uncertain. We retrieved gene expression and clinical data from the TCGA and GEO databases for HCC samples and established a new lysosome-associated prognostic therapeutic index (LAPTI) based on lysosome-related genes through machine learning. We then systematically analysed clinical characteristics, functional enrichment, tumour immune microenvironment, molecular docking, chemotherapy response and immunotherapy response in HCC. LAPTI, composed of four lysosome-related genes (CTSV, LAPTM4B, DNAJC6, AP1M2), is a reliable prognostic indicator for hepatocellular carcinoma patients and is validated in external data sets. Compared with the low LAPTI group, the high LAPTI group showed poorer prognosis and higher immune cell infiltration levels. We also observed that knocking down CTSV in vitro inhibited the proliferation and migration of hepatocellular carcinoma. This study provides valuable insights into the future clinical treatment of hepatocellular carcinoma by accurately assessing the prognosis of patients with hepatocellular carcinoma.

Precise targeting of lipid metabolism in the era of immuno-oncology and the latest advances in nano-based drug delivery systems for cancer therapy

Over the past decade, research has increasingly identified unique dysregulations in lipid metabolism within the tumor microenvironment (TME). Lipids, diverse biomolecules, not only constitute biological membranes but also function as signaling molecules and energy sources. Enhanced synthesis or uptake of lipids in the TME significantly promotes tumorigenesis and proliferation. Moreover, lipids secreted into the TME influence tumor-resident immune cells (TRICs), thereby aiding tumor survival against chemotherapy and immunotherapy. This review aims to highlight recent advancements in understanding lipid metabolism in both tumor cells and TRICs, with a particular emphasis on exogenous lipid uptake and endogenous lipid de novo synthesis. Targeting lipid metabolism for intervention in anticancer therapies offers a promising therapeutic avenue for cancer treatment. Nano-drug delivery systems (NDDSs) have emerged as a means to maximize anti-tumor effects by rewiring tumor metabolism. This review provides a comprehensive overview of recent literature on the development of NDDSs targeting tumor lipid metabolism, particularly in the context of tumor immunotherapy. It covers four key aspects: reprogramming lipid uptake, reprogramming lipolysis, reshaping fatty acid oxidation (FAO), and reshuffling lipid composition on the cell membrane. The review concludes with a discussion of future prospects and challenges in this burgeoning field of research.

LYCHOS is a human hybrid of a plant-like PIN transporter and a GPCR

Lysosomes have crucial roles in regulating eukaryotic metabolism and cell growth by acting as signalling platforms to sense and respond to changes in nutrient and energy availability1. LYCHOS (GPR155) is a lysosomal transmembrane protein that functions as a cholesterol sensor, facilitating the cholesterol-dependent activation of the master protein kinase mechanistic target of rapamycin complex 1 (mTORC1)2. However, the structural basis of LYCHOS assembly and activity remains unclear. Here we determine several high-resolution cryo-electron microscopy structures of human LYCHOS, revealing a homodimeric transmembrane assembly of a transporter-like domain fused to a G-protein-coupled receptor (GPCR) domain. The class B2-like GPCR domain is captured in the apo state and packs against the surface of the transporter-like domain, providing an unusual example of a GPCR as a domain in a larger transmembrane assembly. Cholesterol sensing is mediated by a conserved cholesterol-binding motif, positioned between the GPCR and transporter domains. We reveal that the LYCHOS transporter-like domain is an orthologue of the plant PIN-FORMED (PIN) auxin transporter family, and has greater structural similarity to plant auxin transporters than to known human transporters. Activity assays support a model in which the LYCHOS transporter and GPCR domains coordinate to sense cholesterol and regulate mTORC1 activation.

Predicting Pathologic Complete Response in Locally Advanced Rectal Cancer with [68Ga]Ga-FAPI-04 PET, [18F]FDG PET, and Contrast-Enhanced MRI: Lesion-to-Lesion Comparison with Pathology

Neoadjuvant therapy in patients with locally advanced rectal cancer (LARC) has achieved good pathologic complete response (pCR) rates, potentially eliminating the need for surgical intervention. This study investigated preoperative methods for predicting pCR after neoadjuvant short-course radiotherapy (SCRT) combined with immunochemotherapy. Methods: Treatment-naïve patients with histologically confirmed LARC were enrolled from February 2023 to July 2023. Before surgery, the patients received neoadjuvant SCRT followed by 2 cycles of capecitabine and oxaliplatin plus camrelizumab. 68Ga-labeled fibroblast activation protein inhibitor ([68Ga]Ga-FAPI-04) PET/MRI, [18F]FDG PET/CT, and contrast-enhanced MRI were performed before treatment initiation and before surgery in each patient. PET and MRI features and the size and number of lesions were also collected from each scan. Each parameter's sensitivity, specificity, and diagnostic cutoff were derived via receiver-operating-characteristic curve analysis. Results: Twenty eligible patients (13 men, 7 women; mean age, 60.2 y) were enrolled and completed the entire trial, and all patients had proficient mismatch repair or microsatellite-stable LARC. A postoperative pCR was achieved in 9 patients (45.0%). In the visual evaluation, both [68Ga]Ga-FAPI-04 PET/MRI and [18F]FDG PET/CT were limited to forecasting pCR. Contrast-enhanced MRI had a low sensitivity of 55.56% to predict pCR. In the quantitative evaluation, [68Ga]Ga-FAPI-04 change in SULpeak percentage, where SULpeak is SUVpeak standardized by lean body mass, had the largest area under the curve (0.929) with high specificity (sensitivity, 77.78%; specificity, 100.0%; cutoff, 63.92%). Conclusion: [68Ga]Ga-FAPI-04 PET/MRI is a promising imaging modality for predicting pCR after SCRT combined with immunochemotherapy. The SULpeak decrease exceeding 63.92% may provide valuable guidance in selecting patients who can forgo surgery after neoadjuvant therapy.

PBMC-mediated modulation of macrophage polarization in RAW264.7 cells through STAT1/STAT6 signaling cascades

Peripheral blood mononuclear cells (PBMC), sourced autologously, offer numerous advantages when procured: easier acquisition process, no in vitro amplification needed, decreased intervention and overall increased acceptability make PBMC an attractive candidate for cell therapy treatment. However, the exact mechanism by which PBMC treat diseases remains poorly understood. Immune imbalance is the pathological basis of many diseases, with macrophages playing a crucial role in this process. However, research on the role and mechanisms of PBMC in regulating macrophages remains scarce. This study employed an in vitro co-culture model of PBMC and RAW264.7 macrophages to explore the role and mechanisms of PBMC in regulating macrophages. The results showed that the co-culturing led to decreased expression of inflammatory cytokines and increased expression of anti-inflammatory cytokines in RAW264.7 or in the culture supernatant. Additionally, the pro-inflammatory, tissue matrix-degrading M1 macrophages decreased, while the anti-inflammatory, matrix-synthesizing, regenerative M2 macrophages increased in both RAW264.7 and monocytes within PBMC. Moreover, co-cultured macrophages exhibited a significantly decreased p-STAT1/STAT1 ratio, while the p-STAT6/STAT6 ratio significantly increased. This suggests that PBMC may inhibit M1 macrophage polarization by blocking STAT1 signaling cascades and may promote M2 macrophage polarization through the activation of STAT6 signaling cascades. Overall, this study sheds light on the role and mechanism of PBMC in regulating macrophages. Moreover, it was found that monocytes within co-cultured PBMC differentiated into M2 macrophages in the presence of macrophages. This finding provides experimental evidence for the use of PBMC in treating inflammatory diseases, especially macrophage-depleting inflammatory diseases such as osteoarthritis.

Mn-ZIF nanozymes kill tumors by generating hydroxyl radical as well as reversing the tumor microenvironment

Tumor tissues are well known for their unique high hydrogen peroxide (H2O2) microenvironment. How to exploit this tumor microenvironment for tumor cell killing is a question. In this study, a Mn-doped metal-organic framework (Mn-ZIF) was constructed. It possesses good peroxidase (POD) activity, which can oxidize tumor-localized H2O2 into hydroxyl radicals (·OH), that possesses the ability to directly kill tumor cells. More surprisingly, in vivo experiments the researchers not only observed the tumor-killing effect of Mn-ZIF, but also found it changes in macrophage phenotype in the tumor region. There was an increase in macrophage polarization towards the M1 subtype. This suggests that the tumor-killing effect of Mn-ZIF not only comes from its POD activity, but also regulates the immune microenvironment in the tumor region. In conclusion, the preparation of Mn-ZIF provides a new way for comprehensive tumor therapy.