Effects of bone surface topography and chemistry on macrophage polarization.

Surface structure plays a crucial role in determining cell behavior on biomaterials, influencing cell adhesion, proliferation, differentiation, as well as immune cells and macrophage polarization. While grooves and ridges stimulate M2 polarization and pits and bumps promote M1 polarization, these structures do not accurately mimic the real bone surface. Consequently, the impact of mimicking bone surface topography on macrophage polarization remains unknown. Understanding the synergistic sequential roles of M1 and M2 macrophages in osteoimmunomodulation is crucial for effective bone tissue engineering. Thus, exploring the impact of bone surface microstructure mimicking biomaterials on macrophage polarization is critical. In this study, we aimed to sequentially activate M1 and M2 macrophages using Poly-L-Lactic acid (PLA) membranes with bone surface topographical features mimicked through the soft lithography technique. To mimic the bone surface topography, a bovine femur was used as a model surface, and the membranes were further modified with collagen type-I and hydroxyapatite to mimic the bone surface microenvironment. To determine the effect of these biomaterials on macrophage polarization, we conducted experimental analysis that contained estimating cytokine release profiles and characterizing cell morphology. Our results demonstrated the potential of the hydroxyapatite-deposited bone surface-mimicked PLA membranes to trigger sequential and synergistic M1 and M2 macrophage polarizations, suggesting their ability to achieve osteoimmunomodulatory macrophage polarization for bone tissue engineering applications. Although further experimental studies are required to completely investigate the osteoimmunomodulatory effects of these biomaterials, our results provide valuable insights into the potential advantages of biomaterials that mimic the complex microenvironment of bone surfaces.

Codonopsis pilosula-derived glycopeptide dCP1 promotes the polarization of tumor-associated macrophage from M2-like to M1 phenotype.

The majority of the immune cell population in the tumor microenvironment (TME) consists of tumor-associated macrophages (TAM), which are the main players in coordinating tumor-associated inflammation. TAM has a high plasticity and is divided into two main phenotypes, pro-inflammatory M1 type and anti-inflammatory M2 type, with tumor-suppressive and tumor-promoting functions, respectively. Considering the beneficial effects of M1 macrophages for anti-tumor and the high plasticity of macrophages, the conversion of M2 TAM to M1 TAM is feasible and positive for tumor treatment. This study sought to evaluate whether the glycopeptide derived from simulated digested Codonopsis pilosula extracts could regulate the polarization of M2-like TAM toward the M1 phenotype and the potential regulatory mechanisms. The results showed that after glycopeptide dCP1 treatment, the mRNA relative expression levels of some M2 phenotype marker genes in M2-like TAM in simulated TME were reduced, and the relative expression levels of M1 phenotype marker genes and inflammatory factor genes were increased. Analysis of RNA-Seq of M2-like TAM after glycopeptide dCP1 intervention showed that the gene sets such as glycolysis, which is associated with macrophage polarization in the M1 phenotype, were significantly up-regulated, whereas those of gene sets such as IL-6-JAK-STAT3 pathway, which is associated with polarization in the M2 phenotype, were significantly down-regulated. Moreover, PCA analysis and Pearson's correlation also indicated that M2-like TAM polarized toward the M1 phenotype at the transcriptional level after treatment with the glycopeptide dCP1. Lipid metabolomics was used to further explore the efficacy of the glycopeptide dCP1 in regulating the polarization of M2-like TAM to the M1 phenotype. It was found that the lipid metabolite profiles in dCP1-treated M2-like TAM showed M1 phenotype macrophage lipid metabolism profiles compared with blank M2-like TAM. Analysis of the key differential lipid metabolites revealed that the interconversion between phosphatidylcholine (PC) and diacylglycerol (DG) metabolites may be the central reaction of the glycopeptide dCP1 in regulating the conversion of M2-like TAM to the M1 phenotype. The above results suggest that the glycopeptide dCP1 has the efficacy to regulate the polarization of M2-like TAM to M1 phenotype in simulated TME.

Cigarette smoke sustains immunosuppressive microenvironment inducing M2 macrophage polarization and viability in lung cancer settings.

BACKGROUND: It is amply demonstrated that cigarette smoke (CS) has a high impact on lung tumor progression worsening lung cancer patient prognosis and response to therapies. Alteration of immune cell types and functions in smokers' lungs have been strictly related with smoke detrimental effects. However, the role of CS in dictating an inflammatory or immunosuppressive lung microenvironment still needs to be elucidated. Here, we investigated the effect of in vitro exposure to cigarette smoke extract (CSE) focusing on macrophages. METHODS: Immortalized murine macrophages RAW 264.7 cells were cultured in the presence of CS extract and their polarization has been assessed by Real-time PCR and cytofluorimetric analysis, viability has been assessed by SRB assay and 3D-cultures and activation by exposure to Poly(I:C). Moreover, interaction with Lewis lung carcinoma (LLC1) murine cell models in the presence of CS extract were analyzed by confocal microscopy. RESULTS: Obtained results indicate that CS induces macrophages polarization towards the M2 phenotype and M2-phenotype macrophages are resistant to the CS toxic activity. Moreover, CS impairs TLR3-mediated M2-M1 phenotype shift thus contributing to the M2 enrichment in lung smokers. CONCLUSIONS: These findings indicate that, in lung cancer microenvironment of smokers, CS can contribute to the M2-phenotype macrophages prevalence by different mechanisms, ultimately, driving an anti-inflammatory, likely immunosuppressive, microenvironment in lung cancer smokers.

Ginsenoside Rb1 mitigates acute catecholamine surge-induced myocardial injuries in part by suppressing STING-mediated macrophage activation.

Stress cardiomyopathy (SCM) is associated with cardiovascular mortality rates similar to acute coronary syndrome. Myocardial injuries driven by inflammatory mechanisms may in part account for the dismal prognosis of SCM. Currently, no inflammation-targeted therapies are available to mitigate SCM-associated myocardial injuries. In this study, acute catecholamine surge-induced SCM was modeled by stimulating the ovariectomized (OVX) mice with isoproterenol (ISO). The effects of ginsenoside Rb1 (Rb1) on SCM-associated myocardial injuries were assessed in the OVX-ISO compound mice. RAW 264.7 macrophages stimulated with calf thymus DNA (ctDNA) or STING agonist DMXAA were adopted to further understand the anti-inflammatory mechanisms of Rb1. The results show that estrogen deprivation increases the susceptibility to ISO-induced myocardial injuries. Rb1 mitigates myocardial injuries and attenuates cardiomyocyte necrosis as well as myocardial inflammation in the OVX-ISO mice. Bioinformatics analysis suggests that cytosolic DNA-sensing pathway is closely linked with ISO-triggered inflammatory responses and cell death in the heart. In macrophages, Rb1 lowers ctDNA-stimulated production of TNF-α, IL-6, CCL2 and IFN-ß. RNA-seq analyses uncover that Rb1 offsets DNA-stimulated upregulation in multiple inflammatory response pathways and cytosolic DNA-sensing pathway. Furthermore, Rb1 directly mitigates DMXAA-stimulated STING activation and inflammatory responses in macrophages. In conclusion, the work here demonstrates for the first time that Rb1 protects against SCM-associated myocardial injuries in part by counteracting acute ISO stress-triggered cardiomyocyte necrosis and myocardial inflammation. Moreover, by evidencing that Rb1 downregulates cytosolic DNA-sensing machineries in macrophages, our findings warrant further investigation of therapeutic implications of the anti-inflammatory Rb1 in the treatment of SCM.

The Effect of Methyl-Derivatives of Flavanone on MCP-1, MIP-1ß, RANTES, and Eotaxin Release by Activated RAW264.7 Macrophages.

Chemokines, also known as chemotactic cytokines, stimulate the migration of immune cells. These molecules play a key role in the pathogenesis of inflammation leading to atherosclerosis, neurodegenerative disorders, rheumatoid arthritis, insulin-resistant diabetes, and cancer. Moreover, they take part in inflammatory bowel disease (IBD). The main objective of our research was to determine the activity of methyl-derivatives of flavanone, namely, 2'-methylflavanone (5B), 3'-methylflavanone (6B), 4'-methylflavanone (7B), and 6-methylflavanone (8B), on the releasing of selected cytokines by RAW264.7 macrophages activated by LPS. We determined the concentration of chemokines belonging to the CC chemokine family, namely, MCP-1, MIP-1ß, RANTES, and eotaxin, using the Bio-Plex Magnetic Luminex Assay and the Bio-PlexTM 200 System. Among the tested compounds, only 5B and 6B had the strongest effect on inhibiting the examined chemokines' release by macrophages. Therefore, 5B and 6B appear to be potentially useful in the prevention of diseases associated with the inflammatory process.

IL-10-induced modulation of macrophage polarization suppresses outer-blood-retinal barrier disruption in the streptozotocin-induced early diabetic retinopathy mouse model.

Diabetic retinopathy (DR) is associated with ocular inflammation leading to retinal barrier breakdown, vascular leakage, macular edema, and vision loss. DR is not only a microvascular disease but also involves retinal neurodegeneration, demonstrating that pathological changes associated with neuroinflammation precede microvascular injury in early DR. Macrophage activation plays a central role in neuroinflammation. During DR, the inflammatory response depends on the polarization of retinal macrophages, triggering pro-inflammatory (M1) or anti-inflammatory (M2) activity. This study aimed to determine the role of macrophages in vascular leakage through the tight junction complexes of retinal pigment epithelium, which is the outer blood-retinal barrier (BRB). Furthermore, we aimed to assess whether interleukin-10 (IL-10), a representative M2-inducer, can decrease inflammatory macrophages and alleviate outer-BRB disruption. We found that modulation of macrophage polarization affects the structural and functional integrity of ARPE-19 cells in a co-culture system under high-glucose conditions. Furthermore, we demonstrated that intravitreal IL-10 injection induces an increase in the ratio of anti-inflammatory macrophages and effectively suppresses outer-BRB disruption and vascular leakage in a mouse model of early-stage streptozotocin-induced diabetes. Our results suggest that modulation of macrophage polarization by IL-10 administration during early-stage DR has a promising protective effect against outer-BRB disruption and vascular leakage. This finding provides valuable insights for early intervention in DR.

An integrative epigenome-based strategy for unbiased functional profiling of clinical kinase inhibitors.

More than 500 kinases are implicated in the control of most cellular process in mammals, and deregulation of their activity is linked to cancer and inflammatory disorders. 80 clinical kinase inhibitors (CKIs) have been approved for clinical use and hundreds are in various stages of development. However, CKIs inhibit other kinases in addition to the intended target(s), causing both enhanced clinical effects and undesired side effects that are only partially predictable based on in vitro selectivity profiling. Here, we report an integrative approach grounded on the use of chromatin modifications as unbiased, information-rich readouts of the functional effects of CKIs on macrophage activation. This approach exceeded the performance of transcriptome-based approaches and allowed us to identify similarities and differences among CKIs with identical intended targets, to recognize novel CKI specificities and to pinpoint CKIs that may be repurposed to control inflammation, thus supporting the utility of this strategy to improve selection and use of CKIs in clinical settings.

Baricitinib protects ICIs-related myocarditis by targeting JAK1/STAT3 to regulate Macrophage polarization.

PURPOSE: The emergence of immune checkpoint inhibitors (ICIs) has revolutionized cancer treatment, but these drugs can also cause severe immune-related adverse effects (irAEs), including myocarditis. Researchers have become interested in exploring ways to mitigate this side effect, and one promising avenue is the use of baricitinib, a Janus kinase inhibitor known to have anti-inflammatory properties. This study aimed to examine the potential mechanism by which baricitinib in ICIs-related myocarditis. METHODS: To establish an ICIs-related myocarditis model, BALB/c mice were administered murine cardiac troponin I (cTnI) peptide and anti-mouse programmed death 1 (PD-1) antibodies. Subsequently, baricitinib was administered to the mice via intragastric administration. Echocardiography, HE staining, and Masson staining were performed to evaluate myocardial functions, inflammation, and fibrosis. Immunofluorescence was used to detect macrophages in the cardiac tissue of the mice.In vitro experiments utilized raw264.7 cells to induce macrophage polarization using anti-PD-1 antibodies. Different concentrations of baricitinib were applied to assess cell viability, and the release of pro-inflammatory cytokines was measured. The activation of the JAK1/STAT3 signaling pathway was evaluated through western blot analysis. RESULTS: Baricitinib demonstrated its ability to improve cardiac function and reduce cardiac inflammation, as well as fibrosis induced by ICIs. Mechanistically, baricitinib treatment promoted the polarization of macrophages towards the M2 phenotype. In vitro and in vivo experiments showed that anti-PD-1 promoted the release of inflammatory factors. However, treatment with baricitinib significantly inhibited the phosphorylation of JAK1 and STAT3. Additionally, the use of RO8191 reversed the effects of baricitinib, further confirming our findings. CONCLUSION: Baricitinib demonstrated its potential as a protective agent against ICIs-related myocarditis by modulating macrophage polarization. These findings provide a solid theoretical foundation for the development of future treatments for ICIs-related myocarditis.

ROS-mediated NRF2/p-ERK1/2 signaling-involved mitophagy contributes to macrophages activation induced by CdTe quantum dots.

Cadmium telluride (CdTe) quantum dots (QDs) have garnered significant attention for tumor imaging due to their exceptional properties. However, there remains a need for further investigation into their potential toxicity mechanisms and corresponding enhancements. Herein, CdTe QDs were observed to accumulate in mouse liver, leading to a remarkable overproduction of IL-1ß and IL-6. Additionally, there was evidence of macrophage infiltration and activation following exposure to 12.5 µmol/kg body weight of QDs. To elucidate the underlying mechanism of macrophage activation, CdTe QDs functionalized with 3-mercaptopropionic acid (MPA) were utilized. In vitro experiments revealed that 1.0 µM MPA-CdTe QDs activated PINK1-dependent mitophagy in RAW264.7 macrophages. Critically, the autophagic flux remained unimpeded, as demonstrated by the absence of p62 accumulation, LC3 turnover assay results, and successful fusion of autophagosomes with lysosomes. Mechanically, QDs increased reactive oxygen species (ROS) and mitoROS by damaging both mitochondria and lysosomes. ROS, in turn, inhibited NRF2, resulting in the phosphorylation of ERK1/2 and subsequent activation of mitophagy. Notably, 1.0 µM QDs disrupted lysosomes but autophagic flux was not impaired. Eventually, the involvement of the ROS-NRF2-ERK1/2 pathway-mediated mitophagy in the increase of IL-1ß and IL-6 in macrophages was confirmed using Trolox, MitoTEMPO, ML385, specific siRNAs, and lentivirus-based interventions. This study innovatively revealed the pro-inflammatory rather than anti-inflammatory role of mitophagy in nanotoxicology, shedding new light on the mechanisms of mitochondrial disorders induced by QDs and identifying several molecular targets to comprehend the toxicological mechanisms of CdTe QDs.

Varying ratios of M/G in alginate to modulate macrophages polarization and its application for wound healing in diabetic.

Alginate (SA) comprises repeating unis of ß-1, 4 linked ß-D-mannuronic acid (M) and α-L-guloronic acid (G) in varying proportions. The M/G ratio greatly impacts its anti-inflammatory properties in tissue healing wound, as less knowledge reported. This study examined the performances of both SA and SA hydrogel crosslinked with copper ions (SA-Cu) with different M/G ratios are studied. SA with higher M/G ratios stimulated macrophage migration and shifted from M0 to the pro-inflammatory Ml phenotype, while lower M/G ratios shifted from M1 to the pro-repair M2 phenotype. Furthermore, SA-Cu hydrogels with lower M/G ratios exhibited enhanced cross-linking degree, mechanical and rheological properties, as well Cu releasing rate. The reason may be attributed to a relative easy binding between Cu ions and G unit among Cu ions, M unit and G unit. In vitro cell evaluation showed that SA-Cu hydrogel with M/G ratio of 1:1 activated M2 macrophages and up-regulated anti-inflammatory cytokines expression more effectively than those of SA-Cu ratios (2:1) and (1:2). In vivo, SA-Cu hydrogel with M/G ratio of 1:1 expedited diabetic wound healing, accelerating infiltration and phenotype shift of M2 macrophages, and enhancing anti-inflammatory factors, epithelialization and collagen deposition in healing phases. This research highlights the significant role of M/G ratios in SA materials in influencing macrophage behavior and inflammatory responses, which would benefit its application field.

Modulation of macrophage polarization by secondary cross-linked hyaluronan-dopamine hydrogels.

The inflammatory response plays a critical role in standard tissue repair processes, wherein active modulation of macrophage polarization is necessary for wound healing. Dopamine, a mussel-inspired bioactive material, is widely involved in wound healing, neural/bone/myocardial regeneration, and more. Recent studies indicated that dopamine-modified biomaterials can potentially alter macrophages polarization towards a pro-healing phenotype, thereby enhancing tissue regeneration. Nevertheless the immunoregulatory activity of dopamine on macrophage polarization remains unclear. This study introduces a novel interpenetrating hydrogel to bridge this research gap. The hydrogel, combining varying concentrations of oxidized dopamine with hyaluronic acid hydrogel, allows precise regulation of mechanical properties, antioxidant bioactivity, and biocompatibility. Surprisingly, both in vivo and in vitro outcomes demonstrated that dopamine concentration modulates macrophage polarization, but not linearly. Lower concentration (2 mg/mL) potentially decrease inflammation and facilitate M2 type macrophage polarization. In contrast, higher concentration (10 mg/mL) exhibited a pro-inflammatory tendency in the late stages of implantation. RNA-seq analysis revealed that lower dopamine concentrations induced the M1/M2 transition of macrophages by modulating the NF-κB signaling pathway. Collectively, this research offers valuable insights into the immunoregulation effects of dopamine-integrated biomaterials in tissue repair and regeneration.

Immunosuppressive effects of morphine on macrophage polarization and function.

Macrophages play a pivotal role in safeguarding against a broad spectrum of infections, from viral, bacterial, fungal to parasitic threats and contributing to the immune defense against cancer. While morphine's immunosuppressive effects on immune cells are extensively documented, a significant knowledge gap exists regarding its influence on macrophage polarization and differentiation. Hence, we conducted a study that unveils that prior exposure to morphine significantly impedes the differentiation of bone marrow cells into macrophages. Furthermore, the polarization of macrophages toward the M1 phenotype under M1-inducing conditions experiences substantial impairment, as evidenced by the diminished expression of CD80, CD86, CD40, iNOS, and MHCII. This correlates with reduced expression of M1 phenotypical markers such as iNOS, IL-1ß, and IL-6, accompanied by noticeable morphological, size, and phagocytic alterations. Further, we also observed that morphine affected M2 macrophages. These findings emphasize the necessity for a more comprehensive understanding of the impact of morphine on compromising macrophage function and its potential ramifications for therapeutic approaches.

Ficolin-A induces macrophage polarization to a novel pro-inflammatory phenotype distinct from classical M1.

BACKGROUND: Macrophages are key inflammatory immune cells that orchestrate the initiation and progression of autoimmune diseases. The characters of macrophage in diseases are determined by its phenotype in response to the local microenvironment. Ficolins have been confirmed as crucial contributors to autoimmune diseases, with Ficolin-2 being particularly elevated in patients with autoimmune diseases. However, whether Ficolin-A stimulates macrophage polarization is still poorly understood. METHODS: We investigated the transcriptomic expression profile of murine bone marrow-derived macrophages (BMDMs) stimulated with Ficolin-A using RNA-sequencing. To further confirm a distinct phenotype activated by Ficolin-A, quantitative RT-PCR and Luminex assay were performed in this study. Additionally, we assessed the activation of underlying cell signaling pathways triggered by Ficolin-A. Finally, the impact of Ficolin-A on macrophages were investigated in vivo through building Collagen-induced arthritis (CIA) and Dextran Sulfate Sodium Salt (DSS)-induced colitis mouse models with Fcna-/- mice. RESULTS: Ficolin-A activated macrophages into a pro-inflammatory phenotype distinct to LPS-, IFN-γ- and IFN-γ + LPS-induced phenotypes. The transcriptomic profile induced by Ficolin-A was primarily characterized by upregulation of interleukins, chemokines, iNOS, and Arginase 1, along with downregulation of CD86 and CD206, setting it apart from the M1 and M2 phenotypes. The activation effect of Ficolin-A on macrophages deteriorated the symptoms of CIA and DSS mouse models, and the deletion of Fcna significantly alleviated the severity of diseases in mice. CONCLUSION: Our work used transcriptomic analysis by RNA-Seq to investigate the impact of Ficolin-A on macrophage polarization. Our findings demonstrate that Ficolin-A induces a novel pro-inflammatory phenotype distinct to the phenotypes activated by LPS, IFN-γ and IFN-γ + LPS on macrophages.

Hepatocyte mitochondrial DNA mediates macrophage immune response in liver injury induced by trichloroethylene.

We have previously shown that excessive activation of macrophage proinflammatory activity plays a key role in TCE-induced immune liver injury, but the mechanism of polarization is unclear. Recent studies have shown that TLR9 activation plays an important regulatory role in macrophage polarization. In the present study, we demonstrated that elevated levels of oxidative stress in hepatocytes mediate the release of mtDNA into the bloodstream, leading to the activation of TLR9 in macrophages to regulate macrophage polarization. In vivo experiments revealed that pretreatment with SS-31, a mitochondria-targeting antioxidant peptide, reduced the level of oxidative stress in hepatocytes, leading to a decrease in mtDNA release. Importantly, SS-31 pretreatment inhibited TLR9 activation in macrophages, suggesting that hepatocyte mtDNA may activate TLR9 in macrophages. Further studies revealed that pharmacological inhibition of TLR9 by ODN2088 partially blocked macrophage activation, suggesting that the level of macrophage activation is dependent on TLR9 activation. In vitro experiments involving the extraction of mtDNA from TCE-sensitized mice treated with RAW264.7 cells further confirmed that hepatocyte mtDNA can activate TLR9 in mouse peritoneal macrophages, leading to macrophage polarization. In summary, our study comprehensively confirmed that TLR9 activation in macrophages is dependent on mtDNA released by elevated levels of oxidative stress in hepatocytes and that TLR9 activation in macrophages plays a key role in regulating macrophage polarization. These findings reveal the mechanism of macrophage activation in TCE-induced immune liver injury and provide new perspectives and therapeutic targets for the treatment of OMDT-induced immune liver injury.

Disulfiram treatment suppresses antibody-producing reactions by inhibiting macrophage activation and B cell pyrimidine metabolism.

Antibody responses, involving B cells, CD4 + T cells, and macrophages, are implicated in autoimmune diseases and organ transplant rejection. We have previously shown that inhibiting FROUNT with disulfiram (DSF) suppresses macrophage activation and migration, effectively treating inflammatory diseases. In this study, we investigated the effectiveness of DSF in antibody-producing reactions. Using a heart transplantation mouse model with antibody-mediated rejection, we administered anti-CD8 antibody to exclude cellular rejection. DSF directly inhibited B cell responses in vitro and significantly reduced plasma donor-specific antibodies and graft antibody deposition in vivo, resulting in prolonged survival of the heart graft. DSF also mediated various effects, including decreased macrophage infiltration and increased Foxp3+ regulatory T-cells in the grafts. Additionally, DSF inhibited pyrimidine metabolism-related gene expression induced by B-cell stimulation. These findings demonstrate that DSF modulates antibody production in the immune response complexity by regulating B-cell and macrophage responses.

M2 Macrophage-Derived Extracellular Vesicles Encapsulated in Hyaluronic Acid Alleviate Osteoarthritis by Modulating Macrophage Polarization.

An imbalance between M1 and M2 macrophage polarization is critical in osteoarthritis (OA) development. We investigated the effect of M2 macrophage-derived extracellular vesicles (M2-EVs) to reprogramme macrophages from the M1 to M2 phenotype for OA treatment. M1 macrophages and mouse OA models were treated with M2-EVs. Proteomic analysis was performed to evaluate macrophage polarization in vitro. The OA models were as follows: destabilization of the medial meniscus (DMM) surgery-induced OA and collagenase-induced OA (CIOA). Hyaluronic acid (HA) was used to deliver M2-EVs. M2-EVs decreased macrophage accumulation, repolarized macrophages from the M1 to M2 phenotype, mitigated synovitis, reduced cartilage degradation, alleviated subchondral bone damage, and improved gait abnormalities in the CIOA and DMM models. Moreover, HA increased the retention time of M2-EVs and enhanced the efficiency of M2-EVs in OA treatment. Furthermore, proteomic analysis demonstrated that M2-EVs exhibited a macrophage reprogramming ability similar to IL-4, and the pathways might be the NOD-like receptor (NLR), TNF, NF-κB, and Toll-like receptor (TLR) signaling pathways. M2-EVs reprogrammed macrophages from the M1 to M2 phenotype, which resulted in beneficial effects on cartilage and attenuation of OA severity. In summary, our study indicated that M2-EV-guided reprogramming of macrophages is a promising treatment strategy for OA.

Selenium maintains intestinal epithelial cells to activate M2 macrophages against deoxynivalenol injury.

Selenium (Se) is indispensable in alleviating various types of intestinal injuries. Here, we thoroughly investigated the protective effect of Se on the regulation of the epithelial cell-M2 macrophages pathway in deoxynivalenol (DON)-induced intestinal damage. In the present study, Se has positive impacts on gut health by improving gut barrier function and reducing the levels of serum DON in vivo. Furthermore, our study revealed that Se supplementation increased the abundances of GPX4, p-PI3K, and AKT, decreased the levels of 4-HNE and inhibited ferroptosis. Moreover, when mice were treated with DON and Fer-1(ferroptosis inhibitor), ferroptosis was suppressed and PI3K/AKT pathway was activated. These results indicated that GPX4-PI3K/AKT-ferroptosis was a predominant pathway in DON-induced intestinal inflammation. Interestingly, we discovered that both the number of M2 anti-inflammatory macrophages and the levels of CSF-1 decreased while the pro-inflammatory cytokine IL-6 increased in the intestine and MODE-K cells supernatant. Therefore, Se supplementation activated the CSF-1-M2 macrophages axis, resulting in a decrease in IL-6 expression and an enhancement of the intestinal anti-inflammatory capacity. This study provides novel insights into how intestinal epithelial cells regulate the CSF-1-M2 macrophage pathway, which is essential in maintaining intestinal homeostasis confer to environmental hazardous stimuli.

2-Substituted-4,7-dihydro-4-ethylpyrazolo[1,5-a]pyrimidin-7-ones alleviate LPS-induced inflammation by modulating cell metabolism via CD73 upon macrophage polarization.

Macrophage polarization towards the M1 phenotype under bacterial product-related exposure (LPS) requires a rapid change in gene expression patterns and cytokine production along with a metabolic rewiring. Metabolic pathways and redox reactions are such tightly connected, giving rise to an area of research referred to as immunometabolism. A role in this context has been paid to the master redox-sensitive regulator Nuclear factor erythroid 2-related factor 2 (Nrf2) and to the 5'-ectonucleotidase CD73, a marker related to macrophage metabolism rearrangement under pro-inflammatory conditions. In this light, a cell model of LPS-stimulated macrophages has been established and nine 4,7-dihydro-4-ethylpyrazolo[l,5-a]pyrimidin-7-ones with a potential anti-inflammatory effect have been administered. Our data highlight that two selected compounds (namely, 5 and 8) inhibit the LPS-induced Nrf2 nuclear translocation and ameliorate the activity rate of the antioxidant enzyme catalase. Additionally, the pyridine-containing compound (8) promotes the shift from the pro-inflammatory immunophenotype M1 to the pro-resolving M2 one, by downregulating CD80 and iNOS and by enhancing CD163 and TGFß1 expression. Most importantly, CD73 is modulated by these compounds as well as the lactate production. Our data demonstrate that pyrazolo[l,5-a]pyrimidine derivatives are effective as anti-inflammatory compounds. Furthermore, these pyrazolo[l,5-a]pyrimidines exert their action via CD73-related signaling and modulation of cell metabolism of activated macrophages.

Targeting BRD4 with PROTAC degrader ameliorates LPS-induced acute lung injury by inhibiting M1 alveolar macrophage polarization.

OBJECTIVES: Acute lung injury (ALI) is a highly inflammatory condition with the involvement of M1 alveolar macrophages (AMs) polarization, eventually leading to the development of non-cardiogenic edema in alveolar and interstitial regions, accompanied by persistent hypoxemia. Given the significant mortality rate associated with ALI, it is imperative to investigate the underlying mechanisms of this condition so as to identify potential therapeutic targets. The therapeutic effects of the inhibition of bromodomain containing protein 4 (BRD4), an epigenetic reader, has been proven with high efficacy in ameliorating various inflammatory diseases through mediating immune cell activation. However, little is known about the therapeutic potential of BRD4 degradation in acute lung injury. METHODS: This study aimed to assess the protective efficacy of ARV-825, a novel BRD4-targeted proteolysis targeting chimera (PROTAC), against ALI through histopathological examination in lung tissues and biochemical analysis in bronchoalveolar lavage fluid (BALF). Additionally, the underlying mechanism by which BRD4 regulated M1 AMs was elucidated by using CUT & Tag assay. RESULTS: In this study, we found the upregulation of BRD4 in a lipopolysaccharide (LPS)-induced ALI model. Furthermore, we observed that intraperitoneal administration of ARV-825, significantly alleviated LPS-induced pulmonary pathological changes and inflammatory responses. These effects were accompanied by the suppression of M1 AMs. In addition, our findings revealed that the administration of ARV-825 effectively suppressed M1 AMs by inhibiting the expression of IRF7, a crucial transcriptional factor involved in M1 macrophages. CONCLUSION: Our study suggested that targeting BRD4 using ARV-825 is a potential therapeutic approach for ALI.

Widespread S-persulfidation in activated macrophages as a protective mechanism against oxidative-inflammatory stress.

Acute inflammatory responses often involve the production of reactive oxygen and nitrogen species by innate immune cells, particularly macrophages. How activated macrophages protect themselves in the face of oxidative-inflammatory stress remains a long-standing question. Recent evidence implicates reactive sulfur species (RSS) in inflammatory responses; however, how endogenous RSS affect macrophage function and response to oxidative and inflammatory insults remains poorly understood. In this study, we investigated the endogenous pathways of RSS biogenesis and clearance in macrophages, with a particular focus on exploring how hydrogen sulfide (H2S)-mediated S-persulfidation influences macrophage responses to oxidative-inflammatory stress. We show that classical activation of mouse or human macrophages using lipopolysaccharide and interferon-γ (LPS/IFN-γ) triggers substantial production of H2S/RSS, leading to widespread protein persulfidation. Biochemical and proteomic analyses revealed that this surge in cellular S-persulfidation engaged ∼2% of total thiols and modified over 800 functionally diverse proteins. S-persulfidation was found to be largely dependent on the cystine importer xCT and the H2S-generating enzyme cystathionine γ-lyase and was independent of changes in the global proteome. We further investigated the role of the sulfide-oxidizing enzyme sulfide quinone oxidoreductase (SQOR), and found that it acts as a negative regulator of S-persulfidation. Elevated S-persulfidation following LPS/IFN-γ stimulation or SQOR inhibition was associated with increased resistance to oxidative stress. Upregulation of persulfides also inhibited the activation of the macrophage NLRP3 inflammasome and provided protection against inflammatory cell death. Collectively, our findings shed light on the metabolism and effects of RSS in macrophages and highlight the crucial role of persulfides in enabling macrophages to withstand and alleviate oxidative-inflammatory stress.