Faecalibacterium prausnitzii (F. prausnitzii) has been recognized for its various intestinal and extraintestinal benefits to human. And reduction of F. prausnitzii has been linked to an increased risk of intestinal fibrosis in patients of Crohn\'s disease (CD). In this study, oral administration of either live F. prausnitzii or its extracellular vesicles (FEVs) can markedly mitigate the severity of fibrosis in mice induced by repetitive administration of DSS. In vitro experiment revealed that FEVs were capable of directing the polarization of peripheral blood mononuclear cells (PBMCs) towards an M2b macrophage phenotype, which has been associated with anti-fibrotic activities. This effect of FEV was found to be stable under various conditions that promote the development of pro-fibrotic M1/M2a/M2c macrophages. Proteomics and RNA sequencing were performed to uncover the molecular modulation of macrophages by FEVs. Notably, we found that FEVs reprogramed every metabolism of macrophages by damaging the mitochondria, and inhibited oxidative phosphorylation and glycolysis. Moreover, FEV-treated macrophages showed a decreased expression of PPARγ and an altered lipid processing phenotype characterized by decreased cholesterol efflux, which may promote energy reprogramming. Taken together, these findings identify FEV as a driver of macrophage reprogramming, suggesting that triggering M2b macrophage polarization by oral admiration of FEV may serve as strategy to alleviate hyperfibrotic intestine conditions in CD.

OBJECTIVE: The liver is the main organ of ketogenesis, while ketones are mainly metabolized in peripheral tissues via the critical enzyme 3-oxoacid CoA-transferase 1 (OXCT1). We previously found that ketolysis is reactivated in hepatocellular carcinoma (HCC) cells through OXCT1 expression to promote tumor progression; however, whether OXCT1 regulates antitumor immunity remains unclear.
METHODS: To investigate the expression pattern of OXCT1 in HCC in vivo, we conducted multiplex immunohistochemistry experiments on human HCC specimens. To explore the role of OXCT1 in mouse HCC tumor-associated macrophages (TAMs), we generated LysMcreOXCT1f/f (OXCT1 conditional knockout in macrophages) mice.
RESULTS: Here, we found that inhibiting OXCT1 expression in tumor-associated macrophages reduced CD8+ T-cell exhaustion through the succinate-H3K4me3-Arg1 axis. Initially, we found that OXCT1 was highly expressed in liver macrophages under steady state and that OXCT expression was further increased in TAMs. OXCT1 deficiency in macrophages suppressed tumor growth by reprogramming TAMs toward an antitumor phenotype, reducing CD8+ T-cell exhaustion and increasing CD8+ T-cell cytotoxicity. Mechanistically, high OXCT1 expression induced the accumulation of succinate, a byproduct of ketolysis, in TAMs, which promoted Arg1 transcription by increasing the H3K4me3 level in the Arg1 promoter. In addition, pimozide, an inhibitor of OXCT1, suppressed Arg1 expression as well as TAM polarization toward the protumor phenotype, leading to decreased CD8+ T-cell exhaustion and slower tumor growth. Finally, high expression of OXCT1 in macrophages was positively associated with poor survival in patients with HCC.
CONCLUSIONS: In conclusion, our results demonstrate that OXCT1 epigenetically suppresses antitumor immunity, suggesting that suppressing OXCT1 activity in TAMs could be an effective approach for treating liver cancer.
UNASSIGNED: The intricate metabolism of liver macrophages plays a critical role in shaping hepatocellular carcinoma progression and immune modulation. Targeting macrophage metabolism to counteract immune suppression presents a promising avenue for hepatocellular carcinoma treatment. Herein, we found that the ketogenesis gene OXCT1 was highly expressed in tumor-associated macrophages (TAMs) and promoted tumor growth by reprogramming TAMs toward a protumor phenotype. Pharmacological targeting or genetic downregulation of OXCT1 in TAMs enhances antitumor immunity and slows tumor growth. Our results suggest that suppressing OXCT1 activity in TAMs could be an effective approach for treating liver cancer.

Dysregulated skin microbiota and compromised immune responses are the major etiological factors for non-healing diabetic wounds. Current antibacterial strategies fail to orchestrate immune responses and indiscriminately eradicate bacteria at the wound site, exacerbating the imbalance of microbiota. Drawing inspiration from the beneficial impacts that probiotics possess on microbiota, a living microecological hydrogel containing Lactobacillus plantarum and fructooligosaccharide (LP/FOS@Gel) is formulated to remodel dysregulated skin microbiota and reinstate compromised immune responses, cultivating a conducive environment for optimal wound healing. LP/FOS@Gel acts as an \"evocator,\" skillfully integrating the skin microecology, promoting the proliferation of Lactobacillus, Ralstonia, Muribaculum, Bacillus, and Allobaculum, while eradicating colonized pathogenic bacteria. Concurrently, LP/FOS@Gel continuously generates lactic acid to elicit a reparative macrophage response and impede the activation of the nuclear factor kappa-B pathway, effectively alleviating inflammation. As an intelligent microecological system, LP/FOS@Gel reinstates the skin\'s sovereignty during the healing process and effectively orchestrates the harmonious dialogue between the host immune system and microorganisms, thereby fostering the healing of diabetic infectious wounds. These remarkable attributes render LP/FOS@Gel highly advantageous for pragmatic clinical applications.

Immunogenic cell death (ICD) plays a crucial role in triggering the antitumor immune response in the tumor microenvironment (TME). Recently, considerable attention has been dedicated to ferroptosis, a type of ICD that is induced by intracellular iron and has been demonstrated to change the immune desert status of the TME. However, among cancers that are characterized by an immune desert, such as prostate cancer, strategies for inducing high levels of ferroptosis remain limited. Radiated tumor cell-derived microparticles (RMPs) are radiotherapy mimetics that have been shown to activate the cGAS-STING pathway, induce tumor cell ferroptosis, and inhibit M2 macrophage polarization. RMPs can also act as carriers of agents with biocompatibility. In the present study, we designed a therapeutic system wherein the ferroptosis inducer RSL-3 was loaded into RMPs, which were tested in in vitro and in vivo prostate carcinoma models established using RM-1 cells. The apoptosis inducer CT20 peptide (CT20p) was also added to the RMPs to aggravate ferroptosis. Our results showed that RSL-3- and CT20p-loaded RMPs (RC@RMPs) led to ferroptosis and apoptosis of RM-1 cells. Moreover, CT20p had a synergistic effect on ferroptosis by promoting reactive oxygen species (ROS) production, lipid hydroperoxide production, and mitochondrial instability. RC@RMPs elevated dendritic cell (DC) expression of MHCII, CD80, and CD86 and facilitated M1 macrophage polarization. In a subcutaneously transplanted RM-1 tumor model in mice, RC@RMPs inhibited tumor growth and prolonged survival time via DC activation, macrophage reprogramming, enhancement of CD8+ T cell infiltration, and proinflammatory cytokine production in the tumor. Moreover, combination treatment with anti-PD-1 improved RM-1 tumor inhibition. This study provides a strategy for the synergistic enhancement of ferroptosis for prostate cancer immunotherapies.

Although calcium phosphate has been extensively utilized in orthopedic applications such as spine, limbs, dentistry, and maxillofacial surgery, the lack of osteoinductive properties often hinders its effectiveness in treating bone defects resulting from pathological micro-environment such as tumor surgery, osteoporosis, osteomyelitis, and diabetic. Therefore, a novel bone cement based on magnesium-doped bioactive glass was developed in this study. The moderate release of magnesium ions improved the mechanical properties by controlling the crystal size of hydroxyapatite. Through detailed discussion of element content and heat treatment temperature, it was found that 2Mg-BG-800 was suitable for the construction of bone cement. 2Mg-BG-BC exhibited favorable initial (15 min) and final (30 min) setting time, compressive strength (29.45 MPa), compressive modulus (1851.49 MPa), injectability, and shape-adaptability. Furthermore, Mg-BG-BC demonstrated the ability to enhance the osteogenic differentiation of BMSCs, and induce macrophage polarization towards the M2 phenotype, suggesting its potential for osteoporotic fracture regeneration.

Signaling through Notch receptors intrinsically regulates tumor cell development and growth. Here, we studied the role of the Notch ligand Jagged2 on immune evasion in non-small cell lung cancer (NSCLC). Higher expression of JAG2 in NSCLC negatively correlated with survival. In NSCLC pre-clinical models, deletion of Jag2, but not Jag1, in cancer cells attenuated tumor growth and activated protective anti-tumor T cell responses. Jag2-/- lung tumors exhibited higher frequencies of macrophages that expressed immunostimulatory mediators and triggered T cell-dependent anti-tumor immunity. Mechanistically, Jag2 ablation promoted Nr4a-mediated induction of Notch ligands DLL1/4 on cancer cells. DLL1/4-initiated Notch1/2 signaling in macrophages induced the expression of transcription factor IRF4 and macrophage immunostimulatory functionality. IRF4 expression was required for the anti-tumor effects of Jag2 deletion in lung tumors. Antibody targeting of Jagged2 inhibited tumor growth and activated IRF4-driven macrophage-mediated anti-tumor immunity. Thus, Jagged2 orchestrates immunosuppressive systems in NSCLC that can be overcome to incite macrophage-mediated anti-tumor immunity.

Hepatic ischemia-reperfusion injury(HIRI) remains to be an unsolved risk factor that contributes to organ failure after liver surgery. Our clinical retrospective study showed that lower donor liver CX3-C chemokine receptor-1(CX3CR1) mRNA expression level were correlated with upregulated pro-resolved macrophage receptor MERTK, as well as promoted restoration efficiency of allograft injury in liver transplant. To further characterize roles of CX3CR1 in regulating resolution of HIRI, we employed murine liver partial warm ischemia-reperfusion model by Wt & Cx3cr1-/- mice and the reperfusion time was prolonged from 6 h to 4-7 days. Kupffer cells(KCs) were depleted by clodronate liposome(CL) in advance to focus on infiltrating macrophages, and repopulation kinetics were determined by FACS, IF and RNA-Seq. CX3CR1 antagonist AZD8797 was injected i.p. to interrogate potential pharmacological therapeutic strategies. In vitro primary bone marrow macrophages(BMMs) culture by LXR agonist DMHCA, as well as molecular and functional studies, were undertaken to dissect roles of CX3CR1 in modulating macrophages cytobiological development and resolutive functions. We observed that deficiency or pharmacological inhibition of CX3CR1 facilitated HIRI resolution via promoted macrophages migration in CCR1/CCR5 manner, as well as enhanced MerTK-mediated efferocytosis. Our study demonstrated the critical roles of CX3CR1 in progression of HIRI and identified it as a potential therapeutic target in clinical liver transplantation.

Monocyte-derived macrophages play a key pathogenic role in inflammatory diseases. In the case of rheumatoid arthritis (RA), the presence of specific synovial tissue-infiltrating macrophage subsets is associated with either active disease or inflammation resolution. JAK inhibitors (JAKi) are the first targeted synthetic disease-modifying antirheumatic drugs (tsDMARD) approved for treatment of RA with comparable efficacy to biologics. However, the effects of JAKi on macrophage specification and differentiation are currently unknown. We have analyzed the transcriptional and functional effects of JAKi on human peripheral blood monocyte subsets from RA patients and on the differentiation of monocyte-derived macrophages promoted by granulocyte-macrophage colony-stimulating factor (GM-CSF), a factor that drives the development and pathogenesis of RA. We now report that JAKi Upadacitinib restores the balance of peripheral blood monocyte subsets in RA patients and skewed macrophages towards the acquisition of an anti-inflammatory transcriptional and functional profile in a dose-dependent manner. Upadacitinib-treated macrophages showed a strong positive enrichment of the genes that define synovial macrophages associated to homeostasis/inflammation resolution. Specifically, Upadacitinib-treated macrophages exhibited significantly elevated expression of MAFB and MAFB-regulated genes, elevated inhibitory phosphorylation of GSK3β, and higher phagocytic activity and showed an anti-inflammatory cytokine profile upon activation by pathogenic stimuli. These outcomes were also shared by macrophages exposed to other JAKi (baricitinib, tofacitinib), but not in the presence of the TYK2 inhibitor deucravacitinib. As a whole, our results indicate that JAKi promote macrophage re-programming towards the acquisition of a more anti-inflammatory/pro-resolution profile, an effect that correlates with the ability of JAKi to enhance MAFB expression.

Targeting specific organs and cell types using nanotechnology and sophisticated delivery methods has been at the forefront of applicative biomedical sciences lately. Macrophages are an appealing target for immunomodulation by nanodelivery as they are heavily involved in various aspects of many diseases and are highly plastic in their nature. Their continuum of functional \"polarization\" states has been a research focus for many years yielding a profound understanding of various aspects of these cells. The ability of monocyte-derived macrophages to metamorphose from pro-inflammatory to reparative and consequently to pro-resolving effectors has raised significant interest in its therapeutic potential. Here, we briefly survey macrophages\' ontogeny and various polarization phenotypes, highlighting their function in the inflammation-resolution shift. We review their inducing mediators, signaling pathways, and biological programs with emphasis on the nucleic acid sensing-IFN-I axis. We also portray the polarization spectrum of macrophages and the characteristics of their transition between different subtypes. Finally, we highlighted different current drug delivery methods for targeting macrophages with emphasis on nanotargeting that might lead to breakthroughs in the treatment of wound healing, bone regeneration, autoimmune, and fibrotic diseases.

Idiopathic pulmonary fibrosis (IPF) is characterized by fibrotic matrix deposition and irreversible aberrant tissue remodeling. Their mechanisms of action are associated with the activation of macrophages and a disturbed immune environment. We aim to determine how these activated macrophages influenced the pathogenesis of pulmonary fibrosis. We found the fibrotic areas of IPF patients contained more serum and glucocorticoid-induced kinase 1 (SGK1)-positive and M2-type macrophages. Similarly, bleomycin (BLM)+LPS significantly triggered high expression of SGK1 in the IPF mice, accompanied by destroyed lung structure and function, increased fibrosis markers and disturbed immune microenvironment. Mechanistically, SGK1 markedly promoted the reprogramming of M2-type macrophages in fibrotic lungs by triggering glycogen synthase kinase 3beta (GSK3β)-tat-interacting protein 60 (TIP60)- histone-3 lysine-27 acetylation (H3K27ac) signalings, which further released chemokine (C-C motif) ligand 9 (CCL9) to attract Th17 cells and delivered TGF-β to fibroblasts for synergistically destroying immune microenvironment, which was largely reversed by macrophage depletion in mice. We took macrophages as the entry point to deeply analyze IPF pathogenesis and further provided insights for the development of novel drugs represented by SGK1.