M2 Macrophage Phenotype Research Articles

One arrow two eagles: multifunctional nano-system for macrophage reprogramming and osteoclastogenesis inhibition against inflammatory osteolysis

Inflammatory osteolysis poses a significant worldwide threat to public health. However, current monotherapies, which target either the prevention of the inflammatory response or the attenuation of osteoclast (OC) formation, have limited efficacy due to the complexity of the bone immune system being overlooked. Herein, by means of modifying salmon calcitonin (sCT), a multifunctional nano-system (AuNDs-sCT) was designed to synergistically inhibit OC differentiation and reverse the inflammatory microenvironment against inflammatory osteolysis. On the one hand, AuNDs-sCT effectively restrained OC differentiation by binding to the calcitonin receptors on the surface of OC precursors, resulting in the down-regulation of OC-specific genes and proteins. The targeted capacity of AuNDs-sCT provided a more durable and precise therapeutic effect. On the other hand, AuNDs-sCT exhibited antioxidant and anti-inflammatory effects, which regulated the polarization “switch” from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype in macrophages by the inhibition of NF-κB p65 phosphorylation, thereby effectively reversed the local inflammatory microenvironment. Additionally, AuNDs-sCT served as a promising fluorescent probe, enabling real-time visualization of the therapeutic process. This capability is expected to optimize drug administration and evaluate therapeutic effects. In summary, by inhibiting OC differentiation and reprogramming macrophages, AuNDs-sCT successfully realized drug repurposing and achieved the “one arrow two eagles” therapeutic strategy, which offers a synergistic and effective treatment option for the clinical management of inflammatory osteolysis.

IL-33/ST2 Signaling and its Correlation with Macrophage Heterogeneity and Clinicopathologic Features in Human Intrahepatic Cholangiocarcinoma.

IL-33/ST2 signaling plays crucial roles in the development and progression of various human malignancies. However, its significance in intrahepatic cholangiocarcinoma (ICC) still remains unclear. This study aimed to investigate the expression of IL-33/ST2 signaling and its correlations with macrophage heterogeneity and ICC patients' clinicopathologic features. The expression of different phenotype macrophage markers and IL-33/ST2 signalingrelated markers was detected. The correlation between L-33/ST2 signaling and different phenotype macrophage markers as well as ICC patients' clinicopathologic data was evaluated. Massive heterogeneous cancer cells and PAS-positive cells were observed in tumor tissues. CD68-positive cells accumulated in tumor tissues and expression of both M1 phenotype markers and M2 phenotype macrophage markers was higher in tumor samples than para-carcinoma samples. However, M2 phenotype macrophages represented the dominant macrophage population in ICC tissues. Plasma levels of IL-33, ST2, and MIF were evidently enhanced in ICC patients compared to healthy controls. IL-33/ST2 signaling-related markers exhibited a massive increase in tumor samples than para-carcinoma samples. IL-33 and ST2 expression in ICC tissues was positively associated with M1 and M2 phenotype macrophages. Plasma levels of IL-33, ST2, and MIF were correlated with the diameter of tumor lesions, lymph node metastasis, TNM stage, and tumor differentiation degree. Multivariate analysis demonstrated IL-33 expression to exhibit a correlation with the diameter of tumor lesions, lymph node metastasis, and TNM stage. Additionally, there was a relationship observed between ST2, MIF expression, and diameter of tumor lesions plus TNM stage. IL-33/ST2 signaling exhibited a positive relationship with macrophage heterogeneity in ICC tissues, and upregulated levels of IL-33, ST2, and MIF were associated with aggressive clinicopathologic characteristics. These findings may provide promising diagnostic biomarkers and potential therapeutic strategies for ICC patients targeting IL-33/ST2 signaling.

Chitosan-based self-healing thermosensitive hydrogel loaded with siHMGB1 for treatment of rheumatoid arthritis via macrophage repolarization.

Rheumatoid arthritis (RA) is a prevalent autoimmune disease marked by immune cell activation, particularly macrophages. An imbalance between pro-inflammatory M1 and anti-inflammatory M2 macrophages causes synovial inflammation and joint damage, worsening RA. This study presents a biomacromolecular hydrogel delivery system with apoferritin nanoparticles for effective delivery of small interfering high mobility group protein (siHMGB1). The system was designed to promote the polarization of M1 macrophages to the M2 phenotype by downregulating the HMGB1/TLR4/NF-κB-p65 signaling pathway, offering a potential therapeutic approach for the treatment of RA. The oxidized chondroitin sulfate - chitosan - sodium glycerol β - phosphate - Fn/siHMGB1 (OCF/siHMGB1) hydrogel system possessed temperature-sensitive and self-healing properties, enabling the sustained, stable, and efficient release of siHMGB1 at the affected joint. After effective uptake by macrophages, siHMGB1 could effectively repolarize M1-phenotype macrophages to M2-phenotype via the HMGB1/TLR4/NF-κB-p65 signaling pathway both in vitro and in vivo. Additionally, it suppressed the release of pro-inflammatory cytokines and upregulated anti-inflammatory cytokines, which significantly blocked the TLR4/p65-mediated inflammatory signaling. In conclusion, the siHMGB1-loaded hydrogel delivery system designed in this study is effective in treating RA and highlights the potential of gene therapy to induce repolarization of M1 to M2 macrophages for RA treatment.

Polydopamine Nanoformulations Induced ICD and M1 Phenotype Macrophage Polarization for Enhanced TNBC Synergistic Photothermal Immunotherapy.

Photothermal therapy (PTT) is a promising technology that can achieve the thermal ablation of tumors and induce immunogenic cell death (ICD). However, relying solely on the antitumor immune responses caused by PTT-induced ICD is insufficient to suppress tumor metastasis and recurrence effectively. Fortunately, multifunctional nanoformulation-based synergistic photothermal immunotherapy can eliminate primary and metastatic tumors and inhibit tumor recurrence for a long time. Herein, we select polydopamine (PDA) nanoparticles to serve as the carrier for our nanomedicine as well as a potent photothermal agent and modulator of macrophage polarization. PDA nanoparticles are loaded with the insoluble immune adjuvant Imiquimod (R837) to construct PDA(R837) nanoformulations. These straightforward yet highly effective nanoformulations demonstrate excellent performance, allowing for successful triple-negative breast cancer (TNBC) treatment through synergistic photothermal immunotherapy. Moreover, experimental results showed that PDA(R837) implementation of PTT is effective in the thermal ablation of primary tumors while causing ICD and releasing R837, further promoting dendritic cell (DC) maturation and activating the systemic antitumor immune response. Furthermore, PDA(R837) nanoformulations inhibit tumor metastasis and recurrence and achieve M1 phenotype macrophage polarization, achieving long-term and excellent antitumor efficacy. Therefore, the structurally simple PDA(R837) nanoformulations provide cancer treatment and have excellent clinical translational application prospects.

Trophoblast cell-derived extracellular vesicles regulate the polarization of decidual macrophages by carrying miR-141-3p in the pathogenesis of preeclampsia

Dysregulation of macrophage polarization can prevent the invasion of trophoblast cells and further limit spiral artery remodeling in preeclampsia (PE). However, its mechanism is obscure. HTR8-/Svneo cells were cultured under normoxic or hypoxic conditions and extracellular vesicles (EVs) in the culture supernatants were extracted. Next, the cells were incubated with those EVs to investigate their effects on trophoblasts. A co-culture system consisting of HTR8-/Svneo cells and macrophages was used to reveal how the trophoblast-derived EVs affected the macrophage subtype. Finally, a PE mouse model and miR-141-3p knockout mice were used to verify the function of miR-141-3p in PE. Hypoxia induced abnormal increases in the levels of miR-141-3p in HTR8-/Svneo cells and EVs. EVs from hypoxia-treated HTR8-/Svneo cells could downregulate PTEN, a potential target of miR-141-3p, and inhibit trophoblast mitophagy and invasion. However, HTR8-/Svneo cells transfected with an miR-141-3p inhibitor could attenuate the influence of EVs. In an HTR8-/Svneo cell plus macrophage co-culture system, hypoxia-pretreated cells promoted the transformation of macrophages into the M1-phenotye, and HTR8-/Svneo invasion was inhibited by the macrophages. MiR-141 from EVs could target and downregulate dual specificity phosphatase 1 (DUSP1) expression in macrophages, induce formation of the M1 macrophage phenotype in THP-1 cells, downregulate DUSP1 expression, and upregulate TAB2/TAK1 signaling. These results were also demonstrated in normal pregnant mice and PE pregnant mice. A hypoxic environment could upregulate miR-141 expression in the EVs of HTR8-/Svneo cells, and THP-1-derived macrophages could uptake EVs releasing miR-141 to downregulate DUSP1 expression and induce the formation of M1 macrophages, which can lead to the development of PE.

LncRNA MEG3 suppresses hepatocellular carcinoma by stimulating macrophage M1 polarization and modulating immune system via inhibiting CSF-1 in vivo/vitro studies

Hepatocellular carcinoma (HCC) is characterized by a complex tumor microenvironment (TME), and long non-coding RNAs (lncRNAs) MEG3 emerged as regulators of macrophage polarization with a negative relationship with colony-stimulating factor 1 (CSF-1). Few studies are on the interplay among MEG3, CSF-1, T helper cells (Th), and the programmed cell death protein 1 and its ligands (PD-1/PD-Ls) in TME of HCC.MEG3 expression in THP-1 macrophages, monitored polarization, and PD-1/PD-Ls expression were through flow cytometry, WB, and RT-qPCR. In co-cultures, the interaction of MEG3, macrophage, and HCC was assayed by ELISA. The invasive and migratory of HCC were assessed through experiments such as CCK-8, clonogenic assay, wound healing, and Transwell. A xenograft mouse model of HCC was established, administered with MEG3 overexpression (OE) or knockdown (KD) constructs, and monitored tumor growth. In vitro, MEG3 OE induced a robust M1 macrophage phenotype, evidenced by elevated expression of M1 markers and a significant increase in Th1 cytokines, with a concomitant decrease in Th2 cytokines. This was paralleled by reduced CSF-1 and PD-1/PD-Ls expression. In contrast, MEG3 KD promoted an M2 phenotype with increased CSF-1 and PD-1/PD-Ls expression, and an upregulation of Th2 cytokines. MEG3 OE inhibited the growth, invasion, and migration of HCC, while the opposite was observed when MEG3 was downregulated. In vivo, MEG3 OE resulted in significantly reduced tumor growth, with decreased PD-1/PD-Ls expression on macrophages and enhanced Th1 response. Conversely, MEG3 KD promoted tumor growth with increased PD-1/PD-Ls and a Th2-skewed immune response. MEG3 modulates the TME by affecting TAMs through CSF-1, thereby influencing the balance of Th1/Th2 cells and altering the expression of PD-1/PD-L1s. This study demonstrates that targeting MEG3 is an effective therapeutic strategy for HCC.

Priming Mesenchymal Stem Cells with Lipopolysaccharide Boosts the Immunomodulatory and Regenerative Activity of Secreted Extracellular Vesicles

Background: Mesenchymal stem cells (MSCs)-derived extracellular vesicles (EVs) have been proposed as an alternative to live-cell administration for Acute Respiratory Distress Syndrome (ARDS). MSC-EVs can be chiefly influenced by the environment to which the MSCs are exposed. Here, lipopolysaccharide (LPS) priming of MSCs was used as a strategy to boost the natural therapeutic potential of the EVs in acute lung injury (ALI). Methods: The regenerative and immunemodulatory effect of LPS-primed MSC-EVs (LPS-EVs) and non-primed MSC-EVs (C-EVs) were evaluated in vitro on alveolar epithelial cells and macrophage-like THP-1 cells. In vivo, ALI was induced in adult male rats by the intrapulmonary instillation of HCl and LPS. Rats (n = 8 to 22/group) were randomized to receive a single bolus (1 × 108 particles) of LPS-EVs, C-EVs, or saline. Lung injury severity was assessed at 72 h in lung tissue and bronchoalveolar lavage. Results: In vitro, LPS-EVs improved wound regeneration and attenuated the inflammatory response triggered by the P. aeruginosa infection, enhancing the M2 macrophage phenotype. In in vivo studies, LPS-EVs, but not C-EVs, significantly decreased the neutrophilic infiltration and myeloperoxidase (MPO) activity in lung tissue. Alveolar macrophages from LPS-EVs-treated animals exhibited a reduced expression of CXCL-1, a key neutrophil chemoattractant. However, both C-EVs and LPS-EVs reduced alveolar epithelial and endothelial permeability, mitigating lung damage. Conclusions: EVs from LPS-primed MSCs resulted in a better resolution of ALI, achieving a greater balance in neutrophil infiltration and activation, while avoiding the complete disruption of the alveolar barrier. This opens new avenues, paving the way for the clinical implementation of cell-based therapies.

Multi-Metallic Nanosheets Reshaping Immunosuppressive Tumor Microenvironment through Augmenting cGAS-STING Innate Activation and Adaptive Immune Responses for Cancer Immunotherapy.

The highly immunosuppressive tumor microenvironment (TME) restricts the efficient activation of immune responses. To restore the surveillance of the immune system for robust activation, vast efforts are devoted to normalizing the TME. Here, a manganese-doped layered double hydroxide (Mn-LDH) is developed for potent anti-tumor immunity by reversing TME. Mn-LDH is synthesized via a one-step hydrothermal method. In addition to the inherent proton neutralization capacity of LDH, the introduction of manganese oxide endows LDH with an additional ability to produce oxygen. Mn-LDH effectively releases Mn2+ and Mg2+ upon exposure to TME with high levels of H+ and H2O2, which activates synthase-stimulator of interferon genes pathway and maintains the cytotoxicity of CD8+ T cells respectively, achieving a cascade-like role in innate and adaptive immunity. The locally administered Mn-LDH facilitated a "hot" network consisting of mature dendritic cells, M1-phenotype macrophages, as well as cytotoxic and helper T cells, significantly inhibiting the growth of primary and distal tumors. Moreover, the photothermal conversion capacity of Mn-LDH sparks more robust therapeutic effects in large established tumor models with a single administration and irradiation. Overall, this study guides the rational design of TME-modulating immunotherapeutics for robust immune activation, providing a clinical candidate for next-generation cancer immunotherapy.

Albumin nanoassembly bi-directionally manipulated ferroptosis in tumor and CD8+T cells for triple-negative breast cancer therapy

Ferroptosis can serve as a potent strategy for regulating cell death via lipid peroxidation and the imbalance of the antioxidant system resulting from iron accumulation in triple-negative breast cancer (TNBC) therapy. However, the ferroptosis accompanied with down-regulation of glutathione peroxidase 4 (GPX4) lead to CD36-mediated tumor-infiltrating CD8+T cells uptaking fatty acids, resulting in the negative action on immunotherapeutic efficacy. Herein, the albumin nanoparticles, abbreviated as LHS NPs, were designed by co-assembly of hemin, linoleic acid-cystamine, and a CD36 inhibitor sulfosuccinimide oleate, to bi-directionally manipulated ferroptosis in tumor and CD8+T cells for TNBC therapy. LHS NPs exerted more efficient reactive oxygen species generation, glutathione depletion and malondialdehyde production by the combinatory strategy of classical and non-classical ferroptosis modes, which amplified the positive action on ferroptosis in tumor cells. Meanwhile, LHS manipulated the negative action of ferroptosis by inhibiting the CD36 mediated-lipid peroxidation in CD8+T cells, thereby activating the immunotherapeutic efficacy with the improvements on induction of immunogenic cell death, proliferation of CD4+CD8+T cells and natural killer cells, alleviation immunosuppressive regulatory T cells and myeloid-derived suppressor cells, and repolarization of the M2- to M1-phenotype tumor-associated macrophages. Thus, LHS NPs demonstrated an improved antitumor efficacy in suppressing the tumor growth and lung metastasis of 4T1-tumor mice. Our work gives novel insights for the bi-directionally manipulating ferroptosis in tumor and CD8+T cells on TNBC chemoimmunotherapy.

Anti-inflammatory effects of 1,7-dihydroxy-3,4-dimethoxyxanthone through inhibition of M1-phenotype macrophages via arginine/mitochondrial axis.

It is known that 1,7-dihydroxy-3,4-dimethoxyxanthone (XAN), derived from Securidaca inappendiculata Hassk., exhibits anti-inflammatory and analgesic activities and inhibits M1 polarization of macrophages. However, its ability to alleviate inflammation induced by pro-inflammatory cytokines in THP-1 cells and its anti-inflammatory mechanisms remain unclear. THP-1 cells were treated with phorbol 12-myristate-13-acetate to differentiate and divided into three groups. They were stimulated with lipopolysaccharide (LPS) and interferon-γ (IFN-γ). The toxicity of XAN was assessed using Cell Counting Kit-8, and the expression of various genes and proteins was analyzed using real-time quantitative polymerase chain reaction, flow cytometry, and western blotting. Transmission electron microscopy was used to observe changes in mitochondrial structure. XAN at concentrations ≤ 10µg/mL did not affect THP-1 cell viability and reduced the mRNA expression of pro-inflammatory factors, including interleukin (IL)-1β, inducible nitric oxide synthase (iNOS), NOD-like receptor thermal protein domain protein 3 (NLRP3), and tumor necrosis factor-α (TNF-α). XAN also increased the levels of anti-inflammatory factors, including chemokine ligand 22, mannose receptor (CD206), IL-10, peroxisome proliferator-activated receptor-γ, and transglutaminase 2. Additionally, XAN downregulated the expression of inflammation-related proteins iNOS, NLRP3, and IL-1β; significantly increased the expression of arginase 1, ornithine decarboxylase, and arginine metabolism-related proteins and genes; inhibited mitochondrial damage; and reduced reactive oxygen species (ROS) generation. XAN enhanced the arginine metabolism pathway, prevented mitochondrial damage, reduced ROS levels, and provided an effective defensive response against LPS/IFN-γ-induced inflammation.

The Systemic Effect of Ischemia Training and Its Impact on Bone Marrow-Derived Monocytes.

Monocytes are innate immune cells that play a central role in inflammation, an essential component during neovascularization. Our recent publication demonstrated that ischemia training by 24 h unilateral occlusion of the femoral artery (FA) can modify bone marrow-derived monocytes (BM-Mono), allowing them to improve collateral remodeling in a mouse model of hindlimb ischemia. Here, we expand on our previous findings, investigating a potential systemic effect of ischemia training and how this training can impact BM-Mono. BM-Mono from mice exposed to ischemia training (24 h) or Sham (same surgical procedure without femoral artery occlusion-ischemia training) procedures were used as donors in adoptive transfer experiments where recipients were subjected to hindlimb ischemia. Donor cells were divided corresponding to the limb from which they were isolated (left-limb previously subjected to 24 h ischemia and right-contralateral limb). Recipients who received 24 h ischemic-trained monocytes isolated from either limb had remarkable blood flow recovery compared to recipients with Sham monocytes (monocytes isolated from Sham group-no ischemia training). Since these data suggested a systemic effect of ischemic training, circulating extracellular vesicles (EVs) were investigated as potential players. EVs were isolated from both groups, 24 h-trained and Sham, and the former showed increased expression of histone deacetylase 1 (HDAC1), which is known to downregulate 24-dehydrocholesterol reductase (Dhcr24) gene expression. Since we previously revealed that ischemia training downregulates Dhcr24 in BM-Mono, we incubated EVs from 24 h-trained and Sham groups with wild-type (WT) BM-Mono and demonstrated that WT BM-Mono incubated with 24 h-trained EVs had lower gene expression of Dhcr24 and an HDAC1 inhibitor blunted this effect. Next, we repeated the adoptive transfer experiment using Dhcr24 KO mice as donors of BM-Mono for WT mice subjected to hindlimb ischemia. Recipients who received Dhcr24 KO BM-Mono had greater limb perfusion than those who received WT BM-Mono. Further, we focused on the 24 h-trained monocytes (which previously showed downregulation of Dhcr24 gene expression and higher desmosterol) to test the expression of a few genes downstream of the desmosterol pathway, confirm the Dhcr24 protein level and assess its differentiation in M2-like macrophage phenotype. We found that 24 h-trained BM-Mono had greater expression of key genes in the desmosterol pathway, such as liver X receptors (LXRs) and ATP-binding cassette transporter (ABCA1), and we confirmed low protein expression of Dhcr24. Further, we demonstrated that ischemic-trained BM-Mono polarized towards an anti-inflammatory M2 macrophage phenotype. Finally, we demonstrated that 24 h-trained monocytes adhere less to endothelial cells, and the same pattern was shown by WT BM-Mono treated with Dhcr24 inhibitor. Ischemia training leads to a systemic effect that, at least in part, involves circulating EVs and potential epigenetic modification in BM-Mono. These ischemic-trained BM-Mono demonstrated an anti-inflammatory phenotype towards M2 macrophage differentiation and less ability to adhere to endothelial cells, which is associated with the downregulation of Dhcr24 in those cells. These data together suggest that Dhcr24 might be an important target within monocytes to improve the outcomes of hindlimb ischemia.

Pyroptosis-associated genes and tumor immune response in endometrial cancer

The occurrence and progression of tumors are linked to the process of pyroptosis. However, the precise involvement of pyroptosis-associated genes (PRGs) in endometrial cancer (EC) remains uncertain. 29 PRGs were identified as being either up-regulated or down-regulated in EC. PRGs subgroup analysis demonstrated distinct survival outcomes and diverse responses to chemotherapy and immune checkpoint blockade therapy. A higher expression of GPX4 and NOD2, coupled with lower levels of CASP6, PRKACA, and NLRP2, were found to be significantly associated with higher overall survival (OS) rates (p < 0.05). Conversely, lower expression of NOD2 was linked to lower progression-free survival (p = 0.021) and advanced tumor stage(p = 0.0024). NOD2, NLRP2, and TNM stages were identified as independent prognostic factors (p < 0.001). The LASSO prognostic model exhibited a notable decrease in OS among EC patients in the high-risk score group (ROC-AUC10-years: 0.799, p = 0.00644). Furthermore, NOD2 displayed a positive correlation with the infiltration of immune cells and the expression of immune checkpoints (p < 0.001). GPX4 and CASP6 are significantly associated with TMB and MSI (RTMB = 0.39; RMSI = 0.23). Additionally, a substantial upregulation of NOD2 was confirmed in both EC cells and tissue, indicating a positive relationship between advanced TNM stage (p < 0.0001) and infiltration of M1 phenotype macrophages. Nonetheless, its impact on patient OS did not reach statistical significance (p = 0.141). Our findings have contributed to the advancement of a prognostic model for EC patients. NOD2 receptor-mediated pyroptosis mechanism potentially regulates tumor immunity and promotes the transformation of macrophages from the M2 phenotype to the M1 phenotype, which significantly impacts the progression of EC.

In situ enzymatic peptide-based nanomedicine with combined effects for enhanced tumor radio-immunotherapy

Despite the combination of radiotherapy and immunotherapy in clinical practice have shown promising synergistic anti-tumor effect, the immunosuppressive tumor microenvironment (TME) remains to be one of stumbling block impeding the therapeutic efficacy of radio-immunotherapy. In this study, in situ self-assembled peptide-based drug delivery systems with multiple effects were constructed for enhancing tumor radio-immunotherapy. The two peptide-drug conjugates could co-assembled into peptide-based nanomedicine on the cancer cell membrane under enzyme catalysis and continuously release small molecular active drugs in the cytoplasm, which combined action lead YAP phosphorylation and nuclear transfer failure. By simutaneously suppressing glycolysis and reactivating the dysfunctional Hippo pathway, the peptide-based nanomedicine also remitted the immunosuppressive TME by reducing lactate levels and the expression of immunosuppressive factors, respectively. As a result, the pro-tumorigenic M2 phenotype of tumor-associated macrophages (TAMs) was decreased and the anti-tumorigenic M1 phenotype of TAMs was increased. Such a dual intervention strategy from cellular metabolic level and gene transcription level not only inhibited tumor cell proliferation but also reversed the immunosuppressive TME, thereby augmenting the combined efficacy of radiotherapy and immune checkpoint blockade (ICB) therapy. The work is anticipated to contribute novel insights into anti-cancer drug targeted delivery and tumor multi-modal synergistic therapy.

Exogenous NT-3 Promotes Phenotype Switch of Resident Macrophages and Improves Sciatic Nerve Injury through AMPK/NF-κB Signaling Pathway.

Neurotrophin-3 (NT-3) is an important family of neurotrophic factors with extensive neurotrophic activity, which can maintain the survival and regeneration of nerve cells. However, the mechanism of NT-3 on macrophage phenotype transformation after sciatic nerve injury is not clear. In this study, we constructed a scientific nerve compression injury animal model and administered different doses of NT-3 treatment through osmotic minipump. 7 days after surgery, we collected sciatic nerve tissue and observed the distribution of macrophage phenotype through iNOS and CD206 immunofluorescence. During the experiment, regular postoperative observations were conducted on rats. After the experiment, sciatic nerve tissue was collected for HE staining, myelin staining, immunofluorescence staining, and Western blot analysis. To verify the role of the AMPK/NF-κB pathway, we applied the AMPK inhibitor Compound C and the NF-κB inhibitor BAY11-7082 to repeat the above experiment. Our experimental results reveal that NT-3 promotes sciatic nerve injury repair and polarization of M2 macrophage phenotype, promotes AMPK activation, and inhibits NF-κB activation. The repair effect of high concentration NT-3 on sciatic nerve injury is significantly enhanced compared to low concentration. Compound C administration can weaken the effect of NT-3, while BAY 11-7082 can enhance the effect of NT-3. In short, NT-3 significantly improves sciatic nerve injury in rats, promotes sciatic nerve function repair, accelerates M2 macrophage phenotype polarization, and improves neuroinflammatory response. The protective effects of NT-3 mentioned above are partially related to the AMPK/NF-κB signal axis.

LED therapy modulates M1/M2 macrophage phenotypes and mitigates dystrophic features in treadmill-trained mdx mice.

The mdx mouse phenotype, aggravated by chronic exercise on a treadmill, makes this murine model more reliable for the study of Duchenne muscular dystrophy (DMD) and allows the efficacy of therapeutic interventions to be evaluated. This study aims to investigate the effects of photobiomodulation by light-emitting diode (LED) therapy on functional, biochemical and morphological parameters in treadmill-trained adult mdx animals. Mdx mice were trained for 30min of treadmill running at a speed of 12m/min, twice a week for 4weeks. The LED therapy (850nm) was applied twice a week to the quadriceps muscle throughout the treadmill running period. LED therapy improved behavioral activity (open field) and muscle function (grip strength and four limb hanging test). Functional benefits correlated with reduced muscle damage; a decrease in the inflammatory process; modulation of the regenerative muscular process and calcium signalling pathways; and a decrease in oxidative stress markers. The striking finding of this work is that LED therapy leads to a shift from the M1 to M2 macrophage phenotype in the treadmill-trained mdx mice, enhancing tissue repair and mitigating the dystrophic features. Our data also imply that the beneficial effects of LED therapy in the dystrophic muscle correlate with the interplay between calcium, oxidative stress and inflammation signalling pathways. Together, these results suggest that photobiomodulation could be a potential adjuvant therapy for dystrophinopathies.

MCC950 promotes diabetic wound healing through modulating macrophage polarization in an MDSC-dependent manner

Diabetic foot ulcers (DFUs) are serious skin injuries whereby the wound healing process is frequently stalled in the inflammatory phase. Currently, there is a lack of effective therapeutic strategies. MCC950, a highly selective nod-like receptor family pyrin domain containing 3 (NLRP3) inhibitor, has been reported to show strong anti-inflammation effects in many diseases. In this study, we unveiled the role of MCC950 in DFU mice model and its underlying molecular mechanisms. MCC950 could significantly accelerate diabetic wound healing, as shown by shortened healing time and better healing quality. Moreover, increased M2 phenotype macrophages and decreased pro-inflammatory genes were observed in MCC950-treated DFU mice. Additionally, myeloid-derived suppressor cells (MDSCs) were significantly increased in blood, spleen and wound tissues at different time courses. Specifically, MCC950 could recruit more MDSCs in an early phase in DFU mice, exerting an anti-inflammation effect. We identified the cell crosstalk between macrophages and MDSCs with MCC950 treatment process. Depleting MDSCs in vivo could eliminate the therapeutic effect of MCC950 on diabetic wound healing through inhibiting M2 macrophage polarization. Besides, MDSCs isolated from the wounds of MCC950 or saline treated mice were cocultured with bone marrow derived macrophage (BMDM) in a transwell system. Results confirmed that MDSCs sorted from MCC950 treated mice caused a significant increased percentage of M2 macrophages. Collectively, our findings suggest that the administration of MCC950 has the potential to accelerate diabetic wound healing by promoting M2 macrophage polarization in an MDSC-dependent manner. This study provides valuable insights into the utilization of pharmacological agents for DFU treatment.

Engineering Ga-doped mesoporous bioactive glass-integrated PEEK implants for immunomodulatory and enhanced osseointegration effects

With the increasing aging population, the demand for orthopedic implants is also growing. Polyether ether ketone (PEEK) is considered a promising material for orthopedic implants due to its excellent biocompatibility. However, the lack of bioactivity and excessive immune response post-implantation often impair bone integration. Therefore, it is urgent to bio-functionalize PEEK-based implants to promote bone integration. This study employs a simple, economical, and feasible method to coat Ga-ion doped bioactive glass nanoparticles (Ga-MBGs) onto sulfonated PEEK surfaces, constructing a multifunctional PEEK-based orthopedic implant. The resulting bio-functionalized PEEK implants promote macrophage M2 phenotype polarization, thus fostering an anti-inflammatory immune microenvironment. Moreover, the direct osteogenic effect of Ga ions and the immuno-osteogenic effect through promoting macrophage M2 polarization enhance osteogenic differentiation potential in vitro and bone integration in vivo. A sequence of in vivo and in vitro experiments substantiates the essential and intricate function of this innovative orthopedic implants. in regulating normal bone immunity and metabolism. Overall, the application of Ga-MBGs provides a simple, economical, and effective method for developing multifunctional orthopedic implants. This surface bio-functionalized PEEK implant, capable of modulating immunity and bone metabolism, holds significant clinical application potential as an orthopedic implant.

Ir(III)‐Based Photosensitizer‐Loaded M1 Macrophage Exosomes for Synergistic Photodynamic Therapy

AbstractThe synthesis of organic photosensitizers with effective reactive oxygen species (ROS) generation remains one of the urgent needs for cancer therapy. In this study, a simple strategy is developed to endow the intrinsic non‐photosensitizer fluorophores with profound ROS‐generating ability upon light irradiation. This strategy is featured by introducing donor–acceptor (D‐A) structured fluorophores as auxiliary ligands into the Ir(III) metal complex, which provides the Ir(III) metal center‐based triplet state (T1) as an energy level springboard to efficiently enhance the energy transition to the D‐A ligand‐based triplet state (T1'). The energy level difference between T1 and T1' can be regulated through altering the cyclometalated ligands of Ir(III), facilitating the energy transfer from T1 to T1' for augmented ROS generation. To improve the pharmacological properties of the obtained D‐A coordinated Ir(III) complex, it is incorporated with the exosomes extracted from M1 phenotype macrophages (M1‐Exos). The generated nanocomplexes are able to trigger synergistic photodynamic therapy, facilitating the reprogramming of tumor‐associated macrophages and eradicating the tumors in mice. This study provides a general strategy to transform non‐photosensitizer fluorophores into effective photosensitizers for biomedical applications.

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

Ethnopharmacological relevanceViral 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 studyTo 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 methodsThe 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. ResultsDiosmetin-7-O-β-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. ConclusionsDG 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.

Exercise Preconditioning of the Donor Liver Decreases Cold Ischemia/Reperfusion Injury in a Mouse Model.

Liver transplantation stands as the primary treatment for end-stage liver disease, with demand surging in recent decades because of expanded indications. However, hepatic ischemia/reperfusion injury can lead to liver transplant failure in both deceased donor and living donor transplantation. This study explored whether preconditioning donor livers through exercise training (ExT) could mitigate cold ischemic injury posttransplantation. Donor C57BL/6 mice underwent ExT via treadmill running or remained sedentary. After 4 wk, the donor liver underwent cold storage and subsequent orthotopic liver transplantation or ex vivo warm reperfusion. Donor liver from mice subjected to ExT showed significantly decreased hepatic injury on reperfusion. Tissue histology revealed decreased sinusoidal congestion, vacuolization, and hepatocellular necrosis in livers from ExT mice, and immunofluorescence staining further revealed a decreased number of apoptotic cells in ExT grafts. Livers from ExT donors expressed decreased intragraft inflammatory cytokines cascade, decreased neutrophil infiltration and neutrophil extracellular traps, and increased M2 phenotype of recipient macrophages compared with grafts from sedentary mice. After cold storage, liver grafts from ExT donors showed decreased accumulation of reactive oxygen species and decreased levels of cytochrome c and high mobility group box 1 released in the liver effluent. In addition, ExT grafts showed upregulated peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and higher levels of mitochondrial content. Similar effects of decreased hepatic injury were observed in wild-type mice when pretreated with a PGC-1α stimulator ZLN005 instead of ExT. These findings suggest that augmenting hepatocytic mitochondrial content through donor exercise or PGC-1α stimulation may offer therapeutic avenues to mitigate postreperfusion inflammation and improve transplant outcomes.