Diosmetin-7-O-ß-D-glucopyranoside from Pogostemonis Herba alleviated SARS-CoV-2-induced pneumonia by reshaping macrophage polarization and limiting viral replication.

ETHNOPHARMACOLOGICAL RELEVANCE: Viral pneumonia is the leading cause of death after SARS-CoV-2 infection. Despite effective at early stage, long-term treatment with glucocorticoids can lead to a variety of adverse effects and limited benefits. The Chinese traditional herb Pogostemonis Herba is the aerial part of Pogostemon Cablin (Blanco) Benth., which has potent antiviral, antibacterial, anti-inflammatory, and anticancer effects. It was used widely for treating various throat and respiratory diseases, including COVID-19, viral infection, cough, allergic asthma, acute lung injury and lung cancer. AIM OF THE STUDY: To investigate the antiviral and anti-inflammatory effects of chemical compounds from Pogostemonis Herba in SARS-CoV-2-infected hACE2-overexpressing mouse macrophage RAW264.7 cells and hACE2 transgenic mice. MATERIALS AND METHODS: The hACE2-overexpressing RAW264.7 cells were exposed with SARS-CoV-2. The cell viability was detected by CCK8 assay and cell apoptotic rate was by flow cytometric assay. The expressions of macrophage M1 phenotype markers (TNF-α and IL-6) and M2 markers (IL-10 and Arg-1) as well as the viral loads were detected by qPCR. The mice were inoculated intranasally with SARS-CoV-2 omicron variant to induce viral pneumonia. The levels of macrophages, neutrophils, and T cells in the lung tissues of infected mice were analyzed by full spectrum flow cytometry. The expressions of key proteins were detected by Western blot assay. RESULTS: Diosmetin-7-O-ß-D-glucopyranoside (DG) presented the strongest anti-SARS-CoV-2 activity. Intervention with DG at the concentrations of 0.625-2.5 µM not only reduced the viral replication, cell apoptosis, and the productions of inflammatory cytokines (IL-6 and TNF-α) in SARS-CoV-2-infected RAW264.7 cells, but also reversed macrophage polarity from M1 to M2 phenotype. Furthermore, treatment with DG (25-100 mg/kg) alleviated acute lung injury, and reduced macrophage infiltration in SARS-COV-2-infected mice. Mechanistically, DG inhibited SARS-COV-2 gene expression and HK3 translation via targeting YTHDF1, resulting in the inactivation of glycolysis-mediated NF-κB pathway. CONCLUSIONS: DG exerted the potent antiviral and anti-inflammatory activities. It reduced pneumonia in SARS-COV-2-infected mice via inhibiting the viral replication and accelerating M2 macrophage polarization via targeting YTHDF1, indicating its potential for COVID-19 treatment.

Silver-quercetin-loaded honeycomb-like Ti-based interface combats infection-triggered excessive inflammation via specific bactericidal and macrophage reprogramming.

Excessive inflammation caused by bacterial infection is the primary cause of implant failure. Antibiotic treatment often fails to prevent peri-implant infection and may induce unexpected drug resistance. Herein, a non-antibiotic strategy based on the synergy of silver ion release and macrophage reprogramming is proposed for preventing infection and bacteria-induced inflammation suppression by the organic-inorganic hybridization of silver nanoparticle (AgNP) and quercetin (Que) into a polydopamine (PDA)-based coating on the 3D framework of porous titanium (SQPdFT). Once the planktonic bacteria (e.g., Escherichia coli, Staphylococcus aureus) reach the surface of SQPdFT, released Que disrupts the bacterial membrane. Then, AgNP can penetrate the invading bacterium and kill them, which further inhibits the biofilm formation. Simultaneously, released Que can regulate macrophage polarization homeostasis via the peroxisome proliferators-activated receptors gamma (PPARγ)-mediated nuclear factor kappa-B (NF-κB) pathway, thereby terminating excessive inflammatory responses. These advantages facilitate the adhesion and osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs), concomitantly suppressing osteoclast maturation, and eventually conferring superior mechanical stability to SQPdFT within the medullary cavity. In summary, owing to its excellent antibacterial effect, immune remodeling function, and pro-osteointegration ability, SQPdFT is a promising protective coating for titanium-based implants used in orthopedic replacement surgery.

Transformation of macrophages into myofibroblasts in fibrosis-related diseases: emerging biological concepts and potential mechanism.

Macrophage-myofibroblast transformation (MMT) transforms macrophages into myofibroblasts in a specific inflammation or injury microenvironment. MMT is an essential biological process in fibrosis-related diseases involving the lung, heart, kidney, liver, skeletal muscle, and other organs and tissues. This process consists of interacting with various cells and molecules and activating different signal transduction pathways. This review deeply discussed the molecular mechanism of MMT, clarified crucial signal pathways, multiple cytokines, and growth factors, and formed a complex regulatory network. Significantly, the critical role of transforming growth factor-ß (TGF-ß) and its downstream signaling pathways in this process were clarified. Furthermore, we discussed the significance of MMT in physiological and pathological conditions, such as pulmonary fibrosis and cardiac fibrosis. This review provides a new perspective for understanding the interaction between macrophages and myofibroblasts and new strategies and targets for the prevention and treatment of MMT in fibrotic diseases.

Mechanism of macrophages in gout: Recent progress and perspective.

Gout represents an autoinflammatory disorder instigated by monosodium urate crystals. Its primary manifestation involves the recruitment of diverse immune cell populations, including neutrophils and macrophages. Macrophages assume a pivotal role in the initiation of acute gouty inflammation and subsequent inflammatory cascades. However, recent investigations have revealed that the impact of macrophages on gout is nuanced, extending beyond a solely detrimental influence. Macrophages, characterized by different subtypes, exhibit distinct functionalities that either contribute to the progression or regression of gout. A strategy aimed at modulating macrophage polarization, rather than merely inhibiting inflammation, holds promise for enhancing the efficacy of acute gout treatment. This review centres on elucidating potential mechanisms underlying macrophage polarization in the onset and resolution of gouty inflammation, offering novel insights into the immune equilibrium of macrophages in the context of gout.

A combined analysis of bulk RNA-seq and scRNA-seq was performed to investigate the molecular mechanisms associated with the occurrence of myocardial infarction.

BACKGROUND: Myocardial infarction (MI) induces complex transcriptional changes across diverse cardiac cell types. Single-cell RNA sequencing (scRNA-seq) provides an unparalleled ability to discern cellular diversity during infarction, yet the veracity of these discoveries necessitates confirmation. This investigation sought to elucidate MI mechanisms by integrating scRNA-seq and bulk RNA-seq data. METHODS: Publicly available scRNA-seq (GSE136088) and bulk RNA-seq (GSE153485) data from mice MI models were analyzed. Cell types were annotated, and differential expression analysis conducted. Bulk RNA-seq underwent quality control, principal component analysis, and differential expression analysis. RESULTS: In scRNA-seq data, the comparison between MI and sham groups unveiled a reduction in endothelial cell populations, but macrophages and monocytes increased. Within fibroblast subgroups, three distinct categories were discerned, with two exhibiting upregulation in MI. Notably, endothelial cells exhibited an elevated expression of genes associated with apoptosis and ferroptosis. In bulk RNA-seq analysis, distinct patterns emerged when comparing MI and sham groups. Specifically, six genes linked to endothelial ferroptosis exhibited heightened expression in MI group, thereby corroborating the scRNA-seq findings. Moreover, the examination of isolated cardiac macrophages from mice MI model revealed increased expression of Spp1, Col1a2, Col3a1, Ctsd, and Lgals3 compared to sham group, thus substantiating the dysregulation of macrophage apoptosis-related proteins following MI. CONCLUSION: MI altered the transcriptomic landscapes of cardiac cells with increased expression of apoptotic genes. Moreover, the upregulation of macrophage apoptosis marker was confirmed within MI models. The presence of endothelial cell depletion and ferroptosis in MI has been demonstrated.

Deletion of TP signaling in macrophages delays liver repair following APAP-induced liver injury by reducing accumulation of reparative macrophage and production of HGF.

BACKGROUND: Acetaminophen (APAP)-induced liver injury is the most common cause of acute liver failure. Macrophages are key players in liver restoration following APAP-induced liver injury. Thromboxane A2 (TXA2) and its receptor, thromboxane prostanoid (TP) receptor, have been shown to be involved in tissue repair. However, whether TP signaling plays a role in liver repair after APAP hepatotoxicity by affecting macrophage function remains unclear. METHODS: Male TP knockout (TP-/-) and C57BL/6 wild-type (WT) mice were treated with APAP (300 mg/kg). In addition, macrophage-specific TP-knockout (TP△mac) and control WT mice were treated with APAP. We explored changes in liver inflammation, liver repair, and macrophage accumulation in mice treated with APAP. RESULTS: Compared with WT mice, TP-/- mice showed aggravated liver injury as indicated by increased levels of alanine transaminase (ALT) and necrotic area as well as delayed liver repair as indicated by decreased expression of proliferating cell nuclear antigen (PCNA). Macrophage deletion exacerbated APAP-induced liver injury and impaired liver repair. Transplantation of TP-deficient bone marrow (BM) cells to WT or TP-/- mice aggravated APAP hepatotoxicity with suppressed accumulation of macrophages, while transplantation of WT-BM cells to WT or TP-/- mice attenuated APAP-induced liver injury with accumulation of macrophages in the injured regions. Macrophage-specific TP-/- mice exacerbated liver injury and delayed liver repair, which was associated with increased pro-inflammatory macrophages and decreased reparative macrophages and hepatocyte growth factor (HGF) expression. In vitro, TP signaling facilitated macrophage polarization to a reparative phenotype. Transfer of cultured BM-derived macrophages from control mice to macrophage-specific TP-/- mice attenuated APAP-induced liver injury and promoted liver repair. HGF treatment mitigated APAP-induced inflammation and promoted liver repair after APAP-induced liver injury. CONCLUSIONS: Deletion of TP signaling in macrophages delays liver repair following APAP-induced liver injury, which is associated with reduced accumulation of reparative macrophages and the hepatotrophic factor HGF. Specific activation of TP signaling in macrophages may be a potential therapeutic target for liver repair and regeneration after APAP hepatotoxicity.

Punicalagin as a novel selective aryl hydrocarbon receptor (AhR) modulator upregulates AhR expression through the PDK1/p90RSK/AP-1 pathway to promote the anti-inflammatory response and bactericidal activity of macrophages.

Aryl hydrocarbon receptor (AhR) plays an important role in inflammation and immunity as a new therapeutic target for infectious disease and sepsis. Punicalagin (PUN) is a Chinese herbal monomer extract of pomegranate peel that has beneficial anti-inflammatory, antioxidant and anti-infective effects. However, whether PUN is a ligand of AhR, its effect on AhR expression, and its signaling pathway remain poorly understood. In this study, we found that PUN was a unique polyphenolic compound that upregulated AhR expression at the transcriptional level, and regulated the AhR nongenomic pathway. AhR expression in lipopolysaccharide-induced macrophages was upregulated by PUN in vitro and in vivo in a time- and dose-dependent manner. Using specific inhibitors and siRNA, induction of AhR by PUN depended on sequential phosphorylation of 90-kDa ribosomal S6 kinase (p90RSK), which was activated by the mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) and phosphoinositide-dependent protein kinase (PDK)1 pathways. PUN promoted p90RSK-mediated activator protein-1 (AP-1) activation. AhR knockout or inhibitors reversed suppression of interleukin (IL)-6 and IL-1ß expression by PUN. PUN decreased Listeria load and increased macrophage survival via AhR upregulation. In conclusion, we identified PUN as a novel selective AhR modulator involved in AhR expression via the MEK/ERK and PDK1 pathways targeting p90RSK/AP-1 in inflammatory macrophages, which inhibited macrophage inflammation and promoted bactericidal activity.

IL-4-Induced Gene 1: A Potential Player in Myocardial Infarction.

Myocardial infarction (MI), a severe outcome of cardiovascular disease, poses a serious threat to human health. Uncontrolled inflammation and excessive cardiomyocyte death, following an infarction event, significantly contribute to both the mortality rate and complications associated with MI. The protein IL-4-induced gene 1 (IL4I1 or FIG1) serves as a natural inhibitor of innate and adaptive immunity, playing a crucial role in CD4+ T cell differentiation, macrophage polarization, and ferroptosis inhibition. Previous studies have linked IL4I1 to acute MI. This review summarizes evidence from both basic and clinical research, highlighting IL4I1 as a critical immunoregulatory enzyme that not only regulates inflammatory responses, but also potentially mitigates MI-induced damage.

Cross-talk between macrophages and gut microbiota in inflammatory bowel disease: a dynamic interplay influencing pathogenesis and therapy.

Inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn's disease (CD), is a group of chronic immune-mediated gastrointestinal disorders. The etiology of IBD is multifactorial, involving genetic susceptibility, environmental factors, and a complex interplay between the gut microbiota and the host's immune system. Intestinal resident macrophages play an important role in the pathogenesis and progress of IBD, as well as in maintaining intestinal homeostasis and facilitating tissue repair. This review delves into the intricate relationship between intestinal macrophages and gut microbiota, highlighting their pivotal roles in IBD pathogenesis. We discuss the impact of macrophage dysregulation and the consequent polarization of different phenotypes on intestinal inflammation. Furthermore, we explore the compositional and functional alterations in gut microbiota associated with IBD, including the emerging significance of fungal and viral components. This review also examines the effects of current therapeutic strategies, such as 5-aminosalicylic acid (5-ASA), antibiotics, steroids, immunomodulators, and biologics, on gut microbiota and macrophage function. We underscore the potential of fecal microbiota transplantation (FMT) and probiotics as innovative approaches to modulate the gut microbiome in IBD. The aim is to provide insights into the development of novel therapies targeting the gut microbiota and macrophages to improve IBD management.

Embracing multiple infection models to tackle Q fever: A review of in vitro, in vivo, and lung ex vivo models.

Multiple animal and cell culture models are employed to study pathogenesis of Coxiella burnetii, the causative agent of acute and chronic human Q fever. C. burnetii is a lung pathogen that is aerosolized in contaminated products and inhaled by humans to cause acute disease that can disseminate to other organs and establish chronic infection. Cellular models of Q fever include a variety of tissue-derived cell lines from mice and humans such as lung alveolar ex vivo cells. These models have the advantage of being cost-effective and reproducible. Similarly, animal models including mice and guinea pigs are cost-effective, although only immunocompromised SCID mice display a severe disease phenotype in response to Nine Mile I and Nine Mile II isolates of C. burnetii while immunocompetent guinea pigs display human-like symptoms and robust immune responses. Non-human primates such as macaques and marmosets are the closest model of human disease but are costly and largely used for adaptive immune response studies. All animal models are used for vaccine development but many differences exist in the pathogen's ability to establish lung infection when considering infection routes, bacterial isolates, and host genetic background. Similarly, while cellular models are useful for characterization of host-pathogen mechanisms, future developments should include use of a lung infection platform to draw appropriate conclusions. Here, we summarize the current state of the C. burnetii lung pathogenesis field by discussing the contribution of different animal and cell culture models and include suggestions for continuing to move the field forward.

Macrophages dying from ferroptosis promote microglia-mediated inflammatory responses during spinal cord injury.

The neurological deficits following traumatic spinal cord injury are associated with severe patient disability and economic consequences. Currently, an increasing number of studies are focusing on the importance of ferroptosis during acute organ injuries. However, the spatial and temporal distribution patterns of ferroptosis during SCI and the details of its role are largely unknown. In this study, in vivo experiments revealed that microglia are in close proximity to macrophages, the major cell type that undergoes ferroptosis following SCI. Furthermore, we found that ferroptotic macrophages aggravate SCI by inducing the proinflammatory properties of microglia. In vitro studies further revealed ferroptotic macrophages increased the expression of IL-1ß, IL-6, and IL-23 in microglia. Mechanistically, due to the activation of the NF-κB signaling pathway, the expression of IL-1ß and IL-6 was increased. In addition, we established that increased levels of oxidative phosphorylation cause mitochondrial reactive oxygen species generation and unfolded protein response activation and trigger an inflammatory response marked by an increase in IL-23 production. Our findings identified that targeting ferroptosis and IL-23 could be an effective strategy for promoting neurological recovery after SCI.

Siglecs as modulators of macrophage phenotype and function.

The sialic acid-binding immunoglobulin-like lectins (Siglecs) are a family of receptors expressed widely on cells of the hematopoietic system. Siglecs recognize terminal sialic acid residues on glycans and often initiate intracellular signaling upon ligation. Cells can express several Siglec family members concurrently with each showing differential specificities for sialic acid linkages to the underlying glycan as well as varied hydroxyl substitutions, allowing these receptors to fine tune downstream responses. Macrophages are among the many immune cells that express Siglec family members. Macrophages exhibit wide diversity in their phenotypes and functions, and this diversity is often mediated by signals from the local environment, including those from glycans. In this review, we detail the known expression of Siglecs in macrophages while focusing on their functional importance and potential clinical relevance.

Mechanism of LMNB1 activating GPR84 through JAK-STAT pathway to mediate M2 macrophage polarization in lung cancer.

BACKGROUND: It is reported that G protein-coupled receptor 84 (GPR84) can participate in inflammation and immune regulation to repress anti-tumor responses. However, the function of GPR84 in lung cancer (LC) and its potential molecular mechanisms are still largely unknown. METHODS: Bioinformatics and molecular experiments were employed to assess the expression of GPR84 in LC. The pathways enriched by GPR84 were analyzed by the Kyoto Encyclopedia of Genes and Genomes. Bioinformatics prediction identified the potential upstream regulatory factors of GPR84, which were verified through dual luciferase and chromatin immunoprecipitation experiments. Cell viability was measured by methyl thiazolyl tetrazolium assay. The expression levels of key proteins related to the janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway such as JAK2, p-JAK2, p-STAT3, and STAT3 were detected by western blot. Macrophages were co-cultured with LC cells. Flow cytometry was employed to examine the proportion of mannose receptor-positive cells. The expression levels of M2 polarization marker genes chitinase-like protein 3, arginase-1, and found in inflammatory zone 1 were measured by quantitative reverse transcription polymerase chain reaction. We applied an enzyme-linked immunosorbent assay to determine levels of cytokines (interleukin-10 and transforming growth factor beta) to evaluate the M2 macrophage polarization. RESULTS: GPR84 was highly expressed in LC and substantially enriched in the JAK-STAT pathway. GPR84 facilitated the M2 polarization of macrophages in LC. Adding the JAK-STAT pathway inhibitor weakened the promoting effect of GPR84 overexpression on M2 macrophage polarization. Furthermore, GPR84 also had an upstream regulatory factor lamin B1 (LMNB1). Knocking down LMNB1 blocked the JAK-STAT signaling pathway to repress M2 macrophage polarization in LC, while overexpression of GPR84 reversed the impact of LMNB1 knockdown on macrophage polarization. CONCLUSION: The project suggested that the LMNB1/GPR84 axis can facilitate M2 polarization of macrophages in LC by triggering the JAK-STAT pathway. Targeting LMNB1/GPR84 or blocking the JAK-STAT pathway may be a novel approach for LC diagnosis and treatment.

Suramin enhances proliferation, migration, and tendon gene expression of human supraspinatus tenocytes.

Rotator cuff tendinopathy is a common musculoskeletal disorder with limited pharmacological treatment strategies. This study aimed to investigate tenocytes' functional in vitro response from a ruptured supraspinatus tendon to suramin administration and to elucidate whether suramin can enhance tendon repair and modulate the inflammatory response to injury. Tenocytes were obtained from human supraspinatus tendons (n = 6). We investigated the effect of suramin on LPS-induced inflammatory responses and the underlying molecular mechanisms in THP-1 macrophages. Suramin enhanced the proliferation, cell viability, and migration of tenocytes. It also increased the protein expression of PCNA and Ki-67. Suramin-treated tenocytes exhibited increased expression of COL1A1, COL3A1, TNC, SCX, and VEGF. Suramin significantly reduced LPS-induced iNOS, COX2 synthesis, inflammatory cytokine TNF-α production, and inflammatory signaling by influencing the NF-κB pathways in THP-1 cells. Our results suggest that suramin holds great promise as a therapeutic option for treating rotator cuff tendinopathy.

Effects of a bioengineered allogeneic cellular construct on burn-related macrophage phenotype.

Bioengineered allogeneic cellularised constructs (BACC) exert pro-healing effects in burn wounds and skew macrophage phenotype towards a predominately reparative phenotype. However, whether BACC can modulate the phenotype of dysregulated macrophages, like those present in burn wounds, is not known. To better understand the macrophage modulatory characteristics of the BACC, primary human macrophages were polarised to the M2b phenotype, an immunosuppressive phenotype relevant to burn wounds, by simultaneously exposing macrophages to polystyrene plate-coated immunoglobulin G and the endotoxin lipopolysaccharide (LPS). The resulting macrophage phenotype upregulated both inflammatory and reparative genes, and increased secretion of the M2b marker CCL1 compared to five different in vitro macrophage phenotypes. M2b macrophages were cultured with the BACC in the presence or absence of LPS to mimic infection, which is a common occurrence in burn wounds. The BACC caused up-regulation of reparative gene sets and down-regulation of pro-inflammatory gene sets, even when LPS was present in the cell culture media. Co-cultures were maintained for 1, 3, or 5 days in the presence of LPS, and by day 1 both non-activated macrophages and M2b macrophages exhibited signs of endotoxin tolerance, as demonstrated by a reduced secretion of tumour necrosis factor α (TNFα) in response to fresh LPS stimulus. The BACC was not able to prevent endotoxin tolerance, but reparative genes were upregulated in macrophages chronically exposed to LPS. These results suggest that the BACC can promote a reparative phenotype in dysregulated macrophages relevant to the pathophysiology of burns.

Quercetin Promotes the M1-to-M2 Macrophage Phenotypic Switch During Liver Fibrosis Treatment by Modulating the JAK2/STAT3 Signaling Pathway.

OBJECTIVE: To investigate the underlying mechanism by which quercetin (Que) regulates macrophage polarization and its subsequent therapeutic effect on liver fibrosis, an important pathological precondition for hepatocellular carcinoma (HCC). METHODS: In vitro experiments were performed on the RAW264.7 mouse macrophage line. After the induction of M1-type macrophages with LPS, the effects of Que on cell morphology, M1/M2 surface marker expression, cytokine expression, and JAK2/STAT3 expression were analyzed. In vivo, male SD rats were used as a model of CCL4-induced hepatic fibrosis, and the effects of Que on serum aminotransferase levels, the histopathological structure of liver tissues, and macrophage-associated protein expression in liver tissues were analyzed. RESULTS: In vitro experiments revealed that Que can suppress the activation of the JAK2/STAT3 signaling pathway, leading to decreases in the expression of M1 macrophage surface markers and cytokines. Additionally, Que was found to increase the expression of M2 macrophage surface markers and cytokines. In vivo, assays demonstrated that Que significantly ameliorated the development of inflammation and fibrosis in a rat liver fibrosis model. CONCLUSION: Que can inhibit hepatic fibrosis by promoting M1 to M2 macrophage polarization, which could be associated with its ability to suppress the JAK2/STAT3 signaling pathway in macrophages.

Mechanical Force on Hydrogel Implication on Enhanced Drug Release, Antibacterial, and M2 Macrophage Polarization: New Insights Alleviate Diabetic Wound Healing.

Diabetic foot ulcers/chronic wounds are difficult to treat because of dysfunctional macrophage response and decreased phenotype transition from the M1 to M2 status. This causes severe inflammation, less angiogenesis, microbial infections, and small deformation in wound beds, affecting the healing process. The commercial wound dressing material has limited efficacy, poor mechanical strength, extra pain, and new granulated tissue formed in a mesh of gauze. It is desired to create tough, skin-adhesive, antifouling, sustainable M2 phenotype-enabling, and mechanoresponsive drug-releasing hydrogel. To resolve this, zwitterionic poly(sulfobetaine methacrylate) (SB) incorporated with keratin-exfoliated MoS2 and bee-wax nanoparticles were developed to deliver phenytoin upon application of mechanical forces. Human hair keratin was used for exfoliation of MoS2, and bee-wax nanoparticles loaded with phenytoin were used as cross-linkers of SB hydrogel. The cross-linked SB-MO15-B hydrogel has high mechanical properties, with more tensile strength and strain of 118 kPa and 1485%. Under external mechanical force, hydrogel deformed to release phenytoin of 38% (tensile) and 24% (compressive), which was higher compared to static condition (12%). The penetration of phenytoin into skin tissue was also improved by the mechanical force applied to the hydrogel. SB-MO15-B hydrogel effectively activates the polarization of macrophages toward the M2 phenotype, promotes cell proliferation, and also shows superior antibacterial properties. In vivo results demonstrate that hydrogel rapidly promotes diabetic wound repair through fast antiinflammation and M2 macrophage polarization. Therefore, a robust mechanoresponsive hydrogel would provide a new strategy to deliver the drug and also tune the M2 macrophage polarization for chronic wound healing.

N-acetyltransferase 10 affects the proliferation of intrahepatic cholangiocarcinoma and M2-type polarization of macrophages by regulating C-C motif chemokine ligand 2.

BACKGROUND: N-acetyltransferase 10 (NAT10) plays a crucial role in the occurrence and development of various tumors. However, the current regulatory mechanism of NAT10 in tumors is limited to its presence in tumor cells. Here, we aimed to reveal the role of NAT10 in intrahepatic cholangiocarcinoma (ICC) and investigate its effect on macrophage polarization in the tumor microenvironment (TME). METHODS: The correlation between NAT10 and ICC clinicopathology was analyzed using tissue microarray (TMA), while the effect of NAT10 on ICC proliferation was verified in vitro and in vivo. Additionally, the downstream target of NAT10, C-C motif chemokine ligand 2 (CCL2), was identified by Oxford Nanopore Technologies full-length transcriptome sequencing, RNA immunoprecipitation-quantitative polymerase chain reaction, and coimmunoprecipitation experiments. It was confirmed by co-culture that ICC cells could polarize macrophages towards M2 type through the influence of NAT10 on CCL2 protein expression level. Through RNA-sequencing, molecular docking, and surface plasmon resonance (SPR) assays, it was confirmed that berberine (BBR) can specifically bind CCL2 to inhibit ICC development. RESULTS: High expression level of NAT10 was associated with poor clinicopathological manifestations of ICC. In vitro, the knockdown of NAT10 inhibited the proliferative activity of ICC cells and tumor growth in vivo, while its overexpression promoted ICC proliferation. Mechanically, by binding to CCL2 messenger RNA, NAT10 increased CCL2 protein expression level in ICC and their extracellular matrix, thereby promoting the proliferation of ICC cells and M2-type polarization of macrophages. BBR can target CCL2, inhibit ICC proliferation, and reduce M2-type polarization of macrophages. CONCLUSIONS: NAT10 promotes ICC proliferation and M2-type polarization of macrophages by up-regulating CCL2, whereas BBR inhibits ICC proliferation and M2-type polarization of macrophages by inhibiting CCL2.

Immune-response gene 1 deficiency aggravates inflammation-triggered cardiac dysfunction by inducing M1 macrophage polarization and aggravating Ly6Chigh monocyte recruitment.

The immune response gene 1 (IRG1) and its metabolite itaconate are implicated in modulating inflammation and oxidative stress, with potential relevance to sepsis-induced myocardial dysfunction (SIMD). This study investigates their roles in SIMD using both in vivo and in vitro models. Mice were subjected to lipopolysaccharide (LPS)-induced sepsis, and cardiac function was assessed in IRG1 knockout (IRG1-/-) and wild-type mice. Exogenous 4-octyl itaconate (4-OI) supplementation was also examined for its protective effects. In vitro, bone marrow-derived macrophages and RAW264.7 cells were treated with 4-OI following Nuclear factor, erythroid 2 like 2 (NRF2)-small interfering RNA administration to elucidate the underlying mechanisms. Our results indicate that IRG1 deficiency exacerbates myocardial injury during sepsis, while 4-OI administration preserves cardiac function and reduces inflammation. Mechanistic insights reveal that 4-OI activates the NRF2/HO-1 pathway, promoting macrophage polarization and attenuating inflammation. These findings underscore the protective role of the IRG1/itaconate axis in SIMD and suggest a therapeutic potential for 4-OI in modulating macrophage responses.

APP-CD74 axis mediates endothelial cell-macrophage communication to promote kidney injury and fibrosis.

Background: Kidney injuries often carry a grim prognosis, marked by fibrosis development, renal function loss, and macrophage involvement. Despite extensive research on macrophage polarization and its effects on other cells, like fibroblasts, limited attention has been paid to the influence of non-immune cells on macrophages. This study aims to address this gap by shedding light on the intricate dynamics and diversity of macrophages during renal injury and repair. Methods: During the initial research phase, the complexity of intercellular communication in the context of kidney injury was revealed using a publicly available single-cell RNA sequencing library of the unilateral ureteral obstruction (UUO) model. Subsequently, we confirmed our findings using an independent dataset from a renal ischemia-reperfusion injury (IRI) model. We treated two different types of endothelial cells with TGF-ß and co-cultured their supernatants with macrophages, establishing an endothelial cell and macrophage co-culture system. We also established a UUO and an IRI mouse model. Western blot analysis, flow cytometry, immunohistochemistry and immunofluorescence staining were used to validate our results at multiple levels. Results: Our analysis revealed significant changes in the heterogeneity of macrophage subsets during both injury processes. Amyloid ß precursor protein (APP)-CD74 axis mediated endothelial-macrophage intercellular communication plays a dominant role. In the in vitro co-culture system, TGF-ß triggers endothelial APP expression, which subsequently enhances CD74 expression in macrophages. Flow cytometry corroborated these findings. Additionally, APP and CD74 expression were significantly increased in the UUO and IRI mouse models. Immunofluorescence techniques demonstrated the co-localization of F4/80 and CD74 in vivo. Conclusion: Our study unravels a compelling molecular mechanism, elucidating how endothelium-mediated regulation shapes macrophage function during renal repair. The identified APP-CD74 signaling axis emerges as a promising target for optimizing renal recovery post-injury and preventing the progression of chronic kidney disease.