Study on the Role and Mechanism of SLC3A2 in Tumor-Associated Macrophage Polarization and Bladder Cancer Cells Growth.

Background: Solute carrier family 3 member 2 (SLC3A2) is highly expressed in various types of cancers, including bladder cancer (BLCA). However, the role and mechanism of SLC3A2 in the onset and progression of BLCA are still unclear. Methods: The interfering plasmid for SLC3A2 was constructed and transfected into BLCA cells. Cell proliferation, invasion, and migration abilities were assessed to evaluate the impact of SLC3A2 silencing on BLCA cell growth. M1 and M2 macrophage polarization markers were detected to evaluate macrophage polarization. The levels of reactive oxygen species (ROS), lipid peroxidation, and Fe2+, as well as the expression of ferroptosis-related proteins, were measured to assess the occurrence of ferroptosis. Ferroptosis inhibitors were used to verify the mechanism. Results: The experimental results showed that SLC3A2 was highly expressed in BLCA cell lines. The proliferation, invasion, and migration of BLCA cells were reduced after interfering with SLC3A2. Interference with SLC3A2 led to increase the expression of M1 macrophage markers and decreased the expression of M2 macrophage markers in M0 macrophages co-cultured with tumor cells. Additionally, interference with SLC3A2 led to increased levels of ROS, lipid peroxidation, and Fe2+, downregulated the expression of solute carrier family 7 member11 (SLC7A11) and glutathione peroxidase 4 (GPX4), while upregulated the expression of acyl-coA synthetase long chain family member 4 (ACSL4) and transferrin receptor 1 (TFR1) in BLCA cells. However, the impact of SLC3A2 interference on cell proliferation and macrophage polarization was impeded by ferroptosis inhibitors. Conclusion: Interference with SLC3A2 inhibited the growth of BLCA cells and the polarization of tumor-associated macrophages by promoting ferroptosis in BLCA cells.

Macrophage polarization: an important role in inflammatory diseases.

Macrophages are crucial cells in the human body's innate immunity and are engaged in a variety of non-inflammatory reactions. Macrophages can develop into two kinds when stimulated by distinct internal environments: pro-inflammatory M1-like macrophages and anti-inflammatory M2-type macrophages. During inflammation, the two kinds of macrophages are activated alternatively, and maintaining a reasonably steady ratio is critical for maintaining homeostasis in vivo. M1 macrophages can induce inflammation, but M2 macrophages suppress it. The imbalance between the two kinds of macrophages will have a significant impact on the illness process. As a result, there are an increasing number of research being conducted on relieving or curing illnesses by altering the amount of macrophages. This review summarizes the role of macrophage polarization in various inflammatory diseases, including autoimmune diseases (RA, EAE, MS, AIH, IBD, CD), allergic diseases (allergic rhinitis, allergic dermatitis, allergic asthma), atherosclerosis, obesity and type 2 diabetes, metabolic homeostasis, and the compounds or drugs that have been discovered or applied to the treatment of these diseases by targeting macrophage polarization.

Exploring the role of CITED transcriptional regulators in the control of macrophage polarization.

Macrophages are tissue resident innate phagocytic cells that take on contrasting phenotypes, or polarization states, in response to the changing combination of microbial and cytokine signals at sites of infection. During the opening stages of an infection, macrophages adopt the proinflammatory, highly antimicrobial M1 state, later shifting to an anti-inflammatory, pro-tissue repair M2 state as the infection resolves. The changes in gene expression underlying these transitions are primarily governed by nuclear factor kappaB (NF-κB), Janus kinase (JAK)/signal transducer and activation of transcription (STAT), and hypoxia-inducible factor 1 (HIF1) transcription factors, the activity of which must be carefully controlled to ensure an effective yet spatially and temporally restricted inflammatory response. While much of this control is provided by pathway-specific feedback loops, recent work has shown that the transcriptional co-regulators of the CBP/p300-interacting transactivator with glutamic acid/aspartic acid-rich carboxy-terminal domain (CITED) family serve as common controllers for these pathways. In this review, we describe how CITED proteins regulate polarization-associated gene expression changes by controlling the ability of transcription factors to form chromatin complexes with the histone acetyltransferase, CBP/p300. We will also cover how differences in the interactions between CITED1 and 2 with CBP/p300 drive their contrasting effects on pro-inflammatory gene expression.

miRNA-Mediated Fine Regulation of TLR-Induced M1 Polarization.

Macrophage polarization to the M1 spectrum is induced by bacterial cell wall components through stimulation of Toll-like family (TLR) receptors. By orchestrating the expression of relevant mediators of the TLR cascade, as well as associated pathways and feedback loops, macrophage polarization is coordinated to ensure an appropriate immune response. This is central to the successful control of pathogens and the maintenance of health. Macrophage polarization is known to be modulated at both the transcriptional and post-transcriptional levels. In recent years, the miRNA-based post-transcriptional regulation of M1 polarization has received increasing attention from the scientific community. Comparative studies have shown that TLR stimulation alters the miRNA profile of macrophages and that macrophages from the M1 or the M2 spectrum differ in terms of miRNAs expressed. Simultaneously, miRNAs are considered critical post-transcriptional regulators of macrophage polarization. In particular, miRNAs are thought to play a regulatory role in the switch between the early proinflammatory response and the resolution phase. In this review, we will discuss the current state of knowledge on the complex interaction of transcriptional and post-transcriptional regulatory mechanisms that ultimately determine the functionality of macrophages.

Investigating the role of itaconate in macrophage activation and oxidative stress injury in sepsis-associated acute kidney injury.

BACKGROUND: Sepsis may be linked to oxidative stress and can be controlled by itaconate, an activator of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. Nevertheless, the itaconate impact on sepsis-associated acute kidney injury (SA-AKI) has yet to be definitively established. METHODS: We employed SA-AKI mouse model through a cecal ligation and puncture (CLP) procedure for the in vivo investigation of the potential nephroprotective effect of itaconate in this study. A plasmid was transfected into RAW264.7 cells to examine the Nrf2 pathway function after itaconate administration. Finally, the immune-responsive gene 1-knockout (IRG1-/-) mice were used to study the itaconate impacts on oxidative stress-induced SA-AKI. RESULTS: We have shown that 4-octyl itaconate (OI) significantly reduced CD11b-positive macrophage aggregation and activated the Nrf2 pathway in the bone marrow-derived macrophages (BMDM). The impacts of Nrf2 inhibitor ML385 on the anti-inflammatory and antioxidant properties of itaconate were found to be partial. OI inhibited lipopolysaccharide-induced oxidative stress injury in RAW264.7 macrophages and activated Nrf2 in the nucleus to hinder the expression of nuclear factor kappa B p65, thereby suppressing oxidative stress injury in the macrophages. Additionally, the introduction of the transfected plasmid resulted in a partial inhibition of the anti-inflammatory impact of itaconate. The kidney injury caused by sepsis exhibited greater severity in the IRG1-/- mice than in the wild type mice. Exogenous OI partially attenuated the kidney injury induced by sepsis in the IRG1-/- mice and suppressed the oxidative stress injury in macrophages. CONCLUSIONS: This investigation offers new proof to support the itaconate function in the development and progression of SA-AKI and shows a new possible therapeutic agent for the SA-AKI treatment.

L-AP Alleviates Liver Injury in Septic Mice by Inhibiting Macrophage Activation via Suppressing NF-κB and NLRP3 Inflammasome/Caspase-1 Signal Pathways.

Liver injury and progressive liver failure are severe life-threatening complications in sepsis, further worsening the disease and leading to death. Macrophages and their mediated inflammatory cytokine storm are critical regulators in the occurrence and progression of liver injury in sepsis, for which effective treatments are still lacking. l-Ascorbic acid 6-palmitate (L-AP), a food additive, can inhibit neuroinflammation by modulating the phenotype of the microglia, but its pharmacological action in septic liver damage has not been fully explored. We aimed to investigate L-AP's antisepticemia action and the possible pharmacological mechanisms in attenuating septic liver damage by modulating macrophage function. We observed that L-AP treatment significantly increased survival in cecal ligation and puncture-induced WT mice and attenuated hepatic inflammatory injury, including the histopathology of the liver tissues, hepatocyte apoptosis, and the liver enzyme levels in plasma, which were comparable to NLRP3-deficiency in septic mice. L-AP supplementation significantly attenuated the excessive inflammatory response in hepatic tissues of septic mice in vivo and in cultured macrophages challenged by both LPS and ATP in vitro, by reducing the levels of NLRP3, pro-IL-1ß, and pro-IL-18 mRNA expression, as well as the levels of proteins for p-I-κB-α, p-NF-κB-p65, NLRP3, cleaved-caspase-1, IL-1ß, and IL-18. Additionally, it impaired the inflammasome ASC spot activation and reduced the inflammatory factor contents, including IL-1ß and IL-18 in plasma/cultured superannuants. It also prevented the infiltration/migration of macrophages and their M1-like inflammatory polarization while improving their M2-like polarization. Overall, our findings revealed that L-AP protected against sepsis by reducing macrophage activation and inflammatory cytokine production by suppressing their activation in NF-κB and NLRP3 inflammasome signal pathways in septic liver.

Modulatory actions of Echinococcus granulosus antigen B on macrophage inflammatory activation.

Cestodes use own lipid-binding proteins to capture and transport hydrophobic ligands, including lipids that they cannot synthesise as fatty acids and cholesterol. In E. granulosus s.l., one of these lipoproteins is antigen B (EgAgB), codified by a multigenic and polymorphic family that gives rise to five gene products (EgAgB8/1-5 subunits) assembled as a 230 kDa macromolecule. EgAgB has a diagnostic value for cystic echinococcosis, but its putative role in the immunobiology of this infection is still poorly understood. Accumulating research suggests that EgAgB has immunomodulatory properties, but previous studies employed denatured antigen preparations that might exert different effects than the native form, thereby limiting data interpretation. This work analysed the modulatory actions on macrophages of native EgAgB (nEgAgB) and the recombinant form of EgAg8/1, which is the most abundant subunit in the larva and was expressed in insect S2 cells (rEgAgB8/1). Both EgAgB preparations were purified to homogeneity by immunoaffinity chromatography using a novel nanobody anti-EgAgB8/1. nEgAgB and rEgAgB8/1 exhibited differences in size and lipid composition. The rEgAgB8/1 generates mildly larger lipoproteins with a less diverse lipid composition than nEgAgB. Assays using human and murine macrophages showed that both nEgAgB and rEgAgB8/1 interfered with in vitro LPS-driven macrophage activation, decreasing cytokine (IL-1ß, IL-6, IL-12p40, IFN-ß) secretion and ·NO generation. Furthermore, nEgAgB and rEgAgB8/1 modulated in vivo LPS-induced cytokine production (IL-6, IL-10) and activation of large (measured as MHC-II level) and small (measured as CD86 and CD40 levels) macrophages in the peritoneum, although rEgAgB8/1 effects were less robust. Overall, this work reinforced the notion that EgAgB is an immunomodulatory component of E. granulosus s.l. Although nEgAgB lipid's effects cannot be ruled out, our data suggest that the EgAgB8/1 subunit contributes to EgAgB´s ability to regulate the inflammatory activation of macrophages.

Inhibition of ACSS2-mediated histone crotonylation alleviates kidney fibrosis via IL-1ß-dependent macrophage activation and tubular cell senescence.

Histone lysine crotonylation (Kcr), as a posttranslational modification, is widespread as acetylation (Kac); however, its roles are largely unknown in kidney fibrosis. In this study, we report that histone Kcr of tubular epithelial cells is abnormally elevated in fibrotic kidneys. By screening these crotonylated/acetylated factors, a crotonyl-CoA-producing enzyme ACSS2 (acyl-CoA synthetase short chain family member 2) is found to remarkably increase histone 3 lysine 9 crotonylation (H3K9cr) level without influencing H3K9ac in kidneys and tubular epithelial cells. The integrated analysis of ChIP-seq and RNA-seq of fibrotic kidneys reveal that the hub proinflammatory cytokine IL-1ß, which is regulated by H3K9cr, play crucial roles in fibrogenesis. Furthermore, genetic and pharmacologic inhibition of ACSS2 both suppress H3K9cr-mediated IL-1ß expression, which thereby alleviate IL-1ß-dependent macrophage activation and tubular cell senescence to delay renal fibrosis. Collectively, our findings uncover that H3K9cr exerts a critical, previously unrecognized role in kidney fibrosis, where ACSS2 represents an attractive drug target to slow fibrotic kidney disease progression.

The Application of Drugs and Nano-Therapies Targeting Immune Cells in Hypoxic Inflammation.

Immune cells are pivotal in the dynamic interplay between hypoxia and inflammation. During hypoxic conditions, HIF-1α, a crucial transcription factor, facilitates the adaptation of immune cells to the hypoxic micro-environment. This adaptation includes regulating immune cell metabolism, significantly impacting inflammation development. Strategies for anti-inflammatory and hypoxic relief have been proposed, aiming to disrupt the hypoxia-inflammation nexus. Research extensively focuses on anti-inflammatory agents and materials that target immune cells. These primarily mitigate hypoxic inflammation by encouraging M2-macrophage polarization, restraining neutrophil proliferation and infiltration, and maintaining Treg/TH17 balance. Additionally, oxygen-releasing nano-materials play a significant role. By alleviating hypoxia and clearing reactive oxygen species (ROS), these nano-materials indirectly influence immune cell functions. This paper delves into the response of immune cells under hypoxic conditions and the resultant effects on inflammation. It provides a comprehensive overview of various therapies targeting specific immune cells for anti-inflammatory purposes and explores nano-materials that either carry or generate oxygen to alleviate anoxic micro-environments.

New insight into arginine and tryptophan metabolism in macrophage activation during tuberculosis.

Arginine and tryptophan are pivotal in orchestrating cytokine-driven macrophage polarization and immune activation. Specifically, interferon-gamma (IFN-γ) stimulates inducible nitric oxide synthase (iNOS) expression), leading to the conversion of arginine into citrulline and nitric oxide (NO), while Interleukin-4 (IL4) promotes arginase activation, shifting arginine metabolism toward ornithine. Concomitantly, IFN-γ triggers indoleamine 2,3-dioxygenase 1 (IDO1) and Interleukin-4 induced 1 (IL4i1), resulting in the conversion of tryptophan into kynurenine and indole-3-pyruvic acid. These metabolic pathways are tightly regulated by NAD+-dependent sirtuin proteins, with Sirt2 and Sirt5 playing integral roles. In this review, we present novel insights that augment our understanding of the metabolic pathways of arginine and tryptophan following Mycobacterium tuberculosis infection, particularly their relevance in macrophage responses. Additionally, we discuss arginine methylation and demethylation and the role of Sirt2 and Sirt5 in regulating tryptophan metabolism and arginine metabolism, potentially driving macrophage polarization.

Activin A signaling stimulates neutrophil activation and macrophage migration in pancreatitis.

Acute Pancreatitis (AP) is associated with high mortality and current treatment options are limited to supportive care. We found that blockade of activin A (activin) in mice improves outcomes in two murine models of AP. To test the hypothesis that activin is produced early in response to pancreatitis and is maintained throughout disease progression to stimulate immune cells, we first performed digital spatial profiling (DSP) of human chronic pancreatitis (CP) patient tissue. Then, transwell migration assays using RAW264.7 mouse macrophages and qPCR analysis of "neutrophil-like" HL-60 cells were used for functional correlation. Immunofluorescence and western blots on cerulein-induced pancreatitis samples from pancreatic acinar cell-specific Kras knock-in (Ptf1aCreER™; LSL-KrasG12D) and functional WT Ptf1aCreER™ mouse lines mimicking AP and CP to allow for in vivo confirmation. Our data suggest activin promotes neutrophil and macrophage activation both in situ and in vitro, while pancreatic activin production is increased as early as 1 h in response to pancreatitis and is maintained throughout CP in vivo. Taken together, activin is produced early in response to pancreatitis and is maintained throughout disease progression to promote neutrophil and macrophage activation.

Serum amyloid A expression in liver promotes synovial macrophage activation and chronic arthritis via NFAT5.

Nuclear factor of activated T-cells 5 (NFAT5), an osmo-sensitive transcription factor, can be activated by isotonic stimuli, such as infection. It remains unclear, however, whether NFAT5 is required for damage-associated molecular pattern-triggered (DAMP-triggered) inflammation and immunity. Here, we found that several DAMPs increased NFAT5 expression in macrophages. In particular, serum amyloid A (SAA), primarily generated by the liver, substantially upregulated NFAT5 expression and activity through TLR2/4-JNK signalling pathway. Moreover, the SAA-TLR2/4-NFAT5 axis promoted migration and chemotaxis of macrophages in an IL-6- and chemokine ligand 2-dependent (CCL2-dependent) manner in vitro. Intraarticular injection of SAA markedly accelerated macrophage infiltration and arthritis progression in mice. By contrast, genetic ablation of NFAT5 or TLR2/4 rescued the pathology induced by SAA, confirming the SAA-TLR2/4-NFAT5 axis in vivo. Myeloid-specific depletion of NFAT5 also attenuated SAA-accelerated arthritis. Of note, inflammatory arthritis in mice strikingly induced SAA overexpression in the liver. Conversely, forced overexpression of the SAA gene in the liver accelerated joint damage, indicating that the liver contributes to bolstering chronic inflammation at remote sites by secreting SAA. Collectively, this study underscores the importance of the SAA-TLR2/4-NFAT5 axis in innate immunity, suggesting that acute phase reactant SAA mediates mutual interactions between liver and joints and ultimately aggravates chronic arthritis by enhancing macrophage activation.

Treatment with lysophosphatidic acid improves glomerulonephritis through the suppression of macrophage activation in a murine model of systemic lupus erythematosus.

OBJECTIVES: Several therapeutic agents have been developed and used for the clinical treatment of systemic lupus erythematosus (SLE). In cases where SLE is accompanied by severe organ failures, such as neuropsychiatric lupus erythematosus (NPSLE) and acute onset of lupus nephritis, the use of potent immunosuppressive drugs, such as cyclophosphamide, is necessary. However, potent immunosuppressive drugs are known to increase infection risks. Thus, the development of therapeutic agents with novel mechanisms is urgently required. Previously, we reported that treatment with lysophosphatidic acid (LPA) prevents depression-like behaviours by suppressing microglial activation in MRL/lpr mice. In this study, we examined whether the treatment with LPA improves glomerulonephritis by affecting systemic immunity in MRL/lpr mice. METHODS: Eighteen-week-old MRL/lpr mice were treated with a vehicle or LPA for 3 weeks. After treatment, the glomerular inflammation and damage parameters were compared between the 2 groups. Moreover, we examined the effects of LPA on immune cells by flow cytometry using isolated splenocytes. RESULTS: LPA treatment in MRL/lpr mice significantly reduced the daily urinary albumin content and suppressed the CD68-positive cells and Periodic acid-Schiff (PAS)-positive areas in the glomeruli. The treatment also suppressed plasma anti-dsDNA antibodies and inflammatory cytokines in MRL/lpr mice. Although LPA did not significantly affect the total number of splenocytes, the treatment significantly reduced CD11b+Ly6G-Ly6C- cells (mature macrophages), as well as CD11b+Ly6G-Ly6C-CD68+ cells (activated mature macrophages). CONCLUSIONS: These results suggest that LPA may improve glomerulonephritis by suppressing macrophage activation in MRL/lpr mice.

Phospholipase C epsilon-1 (PLCƐ1) mediates macrophage activation and protection against tuberculosis.

Tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) infects up to a quarter of the world's population. Although immune responses can control Mtb infection, 5%-10% of infected individuals can progress to active TB disease (progressors). A myriad of host factors regulate disease progression in TB and a better understanding of immune correlates of protection and disease is pivotal for the development of new therapeutics. Comparison of human whole blood transcriptomic metadata with that of macaque TB progressors and Mtb-infected diversity outbred mice (DO) led to the identification of differentially regulated gene (DEG) signatures, associated with TB progression or control. The current study assessed the function of Phospholipase C epsilon (PLCƐ1), the top downregulated gene across species in TB progressors, using a gene-specific knockout mouse model of Mtb infection and in vitro Mtb-infected bone marrow-derived macrophages. PLCƐ1 gene expression was downregulated in TB progressors across species. PLCε1 deficiency in the mouse model resulted in increased susceptibility to Mtb infection, coincident accumulation of lung myeloid cells, and reduced ability to mount antibacterial responses. However, PLCε1 was not required for the activation and accumulation of T cells in mice. Our results suggest an important early role for PLCƐ1 in shaping innate immune response to TB and may represent a putative target for host-directed therapy.

Targeting STAT6-mediated synovial macrophage activation improves pain in experimental knee osteoarthritis.

BACKGROUND: Pain from osteoarthritis (OA) is one of the top causes of disability worldwide, but effective treatment is lacking. Nociceptive factors are released by activated synovial macrophages in OA, but depletion of synovial macrophages paradoxically worsens inflammation and tissue damage in previous studies. Rather than depleting macrophages, we hypothesized that inhibiting macrophage activation may improve pain without increasing tissue damage. We aimed to identify key mechanisms mediating synovial macrophage activation and test the role of STAT signaling in macrophages on pain outcomes in experimental knee OA. METHODS: We induced experimental knee OA in rats via knee destabilization surgery, and performed RNA sequencing analysis on sorted synovial tissue macrophages to identify macrophage activation mechanisms. Liposomes laden with STAT1 or STAT6 inhibitors, vehicle (control), or clodronate (depletion control) were delivered selectively to synovial macrophages via serial intra-articular injections up to 12 weeks after OA induction. Treatment effects on knee and hindpaw mechanical pain sensitivity were measured during OA development, along with synovitis, cartilage damage, and synovial macrophage infiltration using histopathology and immunofluorescence. Lastly, crosstalk between drug-treated synovial tissue and articular chondrocytes was assessed in co-culture. RESULTS: The majority of pathways identified by transcriptomic analyses in OA synovial macrophages involve STAT signaling. As expected, macrophage depletion reduced pain, but increased synovial tissue fibrosis and vascularization. In contrast, STAT6 inhibition in macrophages led to marked, sustained improvements in mechanical pain sensitivity and synovial inflammation without worsening synovial or cartilage pathology. During co-culture, STAT6 inhibitor-treated synovial tissue had minimal effects on healthy chondrocyte gene expression, whereas STAT1 inhibitor-treated synovium induced changes in numerous cartilage turnover-related genes. CONCLUSION: These results suggest that STAT signaling is a major mediator of synovial macrophage activation in experimental knee OA. STAT6 may be a key mechanism mediating the release of nociceptive factors from macrophages and the development of mechanical pain sensitivity. Whereas therapeutic depletion of macrophages paradoxically increases inflammation and fibrosis, blocking STAT6-mediated synovial macrophage activation may be a novel strategy for OA-pain management without accelerating tissue damage.

Obesity-induced downregulation of miR-192 exacerbates lipopolysaccharide-induced acute lung injury by promoting macrophage activation.

BACKGROUND: Macrophage activation may play a crucial role in the increased susceptibility of obese individuals to acute lung injury (ALI). Dysregulation of miRNA, which is involved in various inflammatory diseases, is often observed in obesity. This study aimed to investigate the role of miR-192 in lipopolysaccharide (LPS)-induced ALI in obese mice and its mechanism of dysregulation in obesity. METHODS: Human lung tissues were obtained from obese patients (BMI ≥ 30.0 kg/m2) and control patients (BMI 18.5-24.9 kg/m2). An obese mouse model was established by feeding a high-fat diet (HFD), followed by intratracheal instillation of LPS to induce ALI. Pulmonary macrophages of obese mice were depleted through intratracheal instillation of clodronate liposomes. The expression of miR-192 was examined in lung tissues, primary alveolar macrophages (AMs), and the mouse alveolar macrophage cell line (MH-S) using RT-qPCR. m6A quantification and RIP assays helped determine the cause of miR-192 dysregulation. miR-192 agomir and antagomir were used to investigate its function in mice and MH-S cells. Bioinformatics and dual-luciferase reporter gene assays were used to explore the downstream targets of miR-192. RESULTS: In obese mice, depletion of macrophages significantly alleviated lung tissue inflammation and injury, regardless of LPS challenge. miR-192 expression in lung tissues and alveolar macrophages was diminished during obesity and further decreased with LPS stimulation. Obesity-induced overexpression of FTO decreased the m6A modification of pri-miR-192, inhibiting the generation of miR-192. In vitro, inhibition of miR-192 enhanced LPS-induced polarization of M1 macrophages and activation of the AKT/ NF-κB inflammatory pathway, while overexpression of miR-192 suppressed these reactions. BIG1 was confirmed as a target gene of miR-192, and its overexpression offset the protective effects of miR-192. In vivo, when miR-192 was overexpressed in obese mice, the activation of pulmonary macrophages and the extent of lung injury were significantly improved upon LPS challenge. CONCLUSIONS: Our study indicates that obesity-induced downregulation of miR-192 expression exacerbates LPS-induced ALI by promoting macrophage activation. Targeting macrophages and miR-192 may provide new therapeutic avenues for obesity-associated ALI.

Puerarin Induces Macrophage M2 Polarization to Exert Antinonalcoholic Steatohepatitis Pharmacological Activity via the Activation of Autophagy.

To determine the protective mechanism of puerarin against nonalcoholic steatohepatitis (NASH), the pharmacodynamic effects of puerarin on NASH were evaluated by using zebrafish, cells, and mice. Western blotting, flow cytometry, immunofluorescence, and qRT-PCR were used to detect the effects of puerarin on RAW264.7 autophagy and polarization. Key target interactions between autophagy and polarization were detected using immunoprecipitation. Puerarin regulated the M1/M2 ratio of RAW 264.7 cells induced by LPS + INF-γ. Transcriptomics revealed that PAI-1 is a key target of puerarin in regulating macrophage polarization. PAI-1 knockout reduced the number of M1-type macrophages and increased the number of M2-type macrophages. Puerarin regulated PAI-1 and was associated with macrophage autophagy. It increased p-ULK1 expression in macrophages and activated autophagic flux, reducing the level of PAI-1 expression. Stat3/Hif-1α and PI3K/AKT signaling pathways regulated the number of macrophage polarization phenotypes, reducing liver lipid droplet formation, alleviating liver structural abnormalities, decreasing the number of cytoplasmic vacuoles, and decreasing the area of blue collagen in NASH mice. Puerarin is a promising dietary component for NASH alleviation.

Sulforaphane Regulates Macrophage M1/M2 Polarization to Attenuate Macrophage-induced Caco-2 Cell Injury in an Inflammatory Environment.

Background: The imbalance between M1 and M2 macrophage activation is closely associated with the pathogenesis of inflammatory bowel diseases (IBDs). Sulforaphane (SFN) plays an important role in the treatment of inflammatory diseases. Objective: To investigate the effect of SFN on macrophage polarization and its underlying regulatory mechanism. Methods: Mouse bone marrow-derived macrophages (BMDMs) were treated with SFN and an Nrf2 inhibitor, Brusatol. M1 macrophages were induced by LPS and IFN-γ stimulation, whereas M2 macrophages were induced by stimulation with IL-4 and IL-13. LPS-stimulated BMDMs were co-cultured with Caco-2 cells. Flow cytometry, qRT-PCR, and Western blot were performed to assess macrophage polarization. Cell function was assessed using CCK8 assay, transepithelial electrical resistance (TEER) assay, and biochemical analysis. Results: Higher concentrations of SFN resulted in better intervention effects, with an optimal concentration of 10 µM. SFN decreased the levels of IL-12, IL-6, and TNF-α, as well as the percentages of CD16/32 in M1 BMDMs. At the same time, SFN increased the levels of YM1, Fizz1, and Arg1 as well as the percentages of CD206+ cells in M2 BMDMs. In addition, SFN enhanced the accumulation of Nrf2, NQO1, and HO-1 in M1 BMDMs, and the downregulation of Nrf2 reversed the regulatory effect of SFN on M1/M2 macrophages. LPS-stimulated BMDMs induced Caco-2 cell damage, which was partially alleviated by SFN. Conclusion: Our findings indicate that SFN may act as an Nrf2 agonist to regulate macrophage polarization from M1 to M2. Furthermore, SFN may represent a potential protective ingredient against IBD.

Preliminary study on the dynamic positron emission tomography imaging with 11C-ER176 to delineate macrophage activation in diabetic gastroparesis.

BACKGROUND: Animal models and human data have suggested macrophage-driven immune dysregulation in diabetic gastroparesis (DG). Translocator protein (TSPO) upregulation has been suggested to indicate activated state of macrophages and ER176 is a high affinity third generation TSPO-specific radioligand. The aim of this study was to determine feasibility of dynamic 11C-ER 176 PET to identify macrophage activation in DG. METHODS: Twelve patients, all females, were recruited (4 DG, 4 diabetics, and 4 healthy volunteers) for 11C-ER 176 PET/CT scanning. The standardized uptake value (SUVmax) in the gastric fundus, body, pylorus, and descending part of the duodenum were compared between three groups using Kruskal-Wallis test to perform the comparisons, and a p-value of 0.05 was considered statistically significant. KEY RESULTS: Age was comparable among the three groups with a median of 53 years. The uptake was higher in pylorus in diabetics compared to DG and healthy (SUVmax healthy 4.6 ± 0.2, diabetics 8.4 ± 4.1, DG 5.5 ± 1.0, p = 0.04). The uptake was similar in gastric fundus (9.0 ± 1.6, 13.1 ± 8.3, 7.8 ± 1.9 respectively, p = 0.3), body (7.7 ± 1.9, 13 ± 9.2, 7.8 ± 1.9 respectively, p = 0.8), and duodenum (6.2 ± 2.1, 9.5 ± 6.8, 7.0 ± 1.8 respectively, p = 0.6). No correlation was observed between SUVmax uptake and either HbA1C or fasting blood glucose. CONCLUSIONS AND INFERENCES: Female diabetic gastroparesis patients did not demonstrate increased TSPO ligand 11C-ER 176 uptake in the stomach. Possible explanations include lack of specificity of ligand for specific macrophage phenotypes in DG, sex effect, or small sample size. Further studies investigating non-invasive ways of analyzing immune dysregulation in neurogastrointestinal disorders are warranted.

Exploring the polarization of M1 and M2 macrophages in the context of skin diseases.

Macrophages are critical components of the immune system and play vital roles in pathogen defense, immune regulation, and tissue repair. These cells exhibit different polarization states depending on environmental signals, and the M1/M2 paradigm is a useful tool for comprehending these states. This review article comprehensively presents the underlying mechanisms of M1 and M2 macrophage polarization and examines their polarization in various skin diseases. Additionally, this paper discusses therapeutic strategies that target M1 and M2 macrophage polarization in skin diseases. A more profound understanding of macrophage polarization in skin diseases could provide valuable insights for the development of innovative therapeutic strategies.