Anti-inflammatory M2 Macrophages Research Articles

Dental Pulp Stem Cell Lysate-Based Hydrogel Improves Diabetic Wound Healing via the Regulation of Anti-Inflammatory Macrophages and Keratinocytes.

The prolonged existence of chronic wounds heightens the risk of patients experiencing chronic pain, necrosis, and amputation. Dental pulp stem cells (DPSCs) have garnered attention due to their potential immunomodulatory and tissue repair regenerative effects in the management of chronic wounds. However, stem-cell-based therapy faces challenges such as malignant differentiation, immune rejection, and long-term effectiveness. To overcome these challenges, we proposed a chronic wound therapy using a hydrogel derived from human-originated dental pulp stem cell lysate (DPSCL). Our data indicate that, with the degradation of the dental pulp stem cell lysate-based hydrogel (DPSCLH), the slowly released cell lysates recruit anti-inflammatory M2 macrophages and promote the proliferation, migration, and keratinization of HacaT cells. In addition, in vivo studies revealed that DPSCLH avoids immune rejection reactions and induces a long-term accumulation of endogenous M2 macrophages. In a mouse model of diabetic wounds, DPSCLH effectively modulates the inflammatory microenvironment around diabetic wounds, promotes the formation of the stratum corneum, and facilitates the healing of wounds, thus holding tremendous potential for the treatment of diabetic wounds.

Therapeutic potential of mesenchymal stem cell-derived extracellular vesicles: A focus on inflammatory bowel disease.

Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have emerged as key regulators of intercellular communication, orchestrating essential biological processes by delivering bioactive cargoes to target cells. Available evidence suggests that MSC-EVs can mimic the functions of their parental cells, exhibiting immunomodulatory, pro-regenerative, anti-apoptotic, and antifibrotic properties. Consequently, MSC-EVs represent a cell-free therapeutic option for patients with inflammatory bowel disease (IBD), overcoming the limitations associated with cell replacement therapy, including their non-immunogenic nature, lower risk of tumourigenicity, cargo specificity and ease of manipulation and storage. This review aims to provide a comprehensive examination of the therapeutic efficacy of MSC-EVs in IBD, with a focus on their mechanisms of action and potential impact on treatment outcomes. We examine the advantages of MSC-EVs over traditional therapies, discuss methods for their isolation and characterisation, and present mechanistic insights into their therapeutic effects through transcriptomic, proteomic and lipidomic analyses of MSC-EV cargoes. We also discuss available preclinical studies demonstrating that MSC-EVs reduce inflammation, promote tissue repair and restore intestinal homeostasis in IBD models, and compare these findings with those of clinical trials. Finally, we highlight the potential of MSC-EVs as a novel therapy for IBD and identify challenges and opportunities associated with their translation into clinical practice. The source of mesenchymal stem cells (MSCs) strongly influences the composition and function of MSC-derived extracellular vesicles (EVs), affecting their therapeutic potential. Adipose-derived MSC-EVs, known for their immunoregulatory properties and ease of isolation, show promise as a treatment for inflammatory bowel disease (IBD). MicroRNAs are consistently present in MSC-EVs across cell types and are involved in pathways that are dysregulated in IBD, making them potential therapeutic agents. For example, miR-let-7a is associated with inhibition of apoptosis, miR-100 supports cell survival, miR-125b helps suppress pro-inflammatory cytokines and miR-20 promotes anti-inflammatory M2 macrophage polarisation. Preclinical studies in IBD models have shown that MSC-EVs reduce intestinal inflammation by suppressing pro-inflammatory mediators (e.g., TNF-α, IL-1β, IL-6) and increasing anti-inflammatory factors (e.g., IL-4, IL-10). They also promote mucosal healing and strengthen the integrity of the gut barrier, suggesting their potential to address IBD pathology.

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.

Histopathology and prognosis of new-onset atrio-ventricular block after coronary artery bypass graft surgery

Abstract Background Atrio-ventricular block (AVB) can often be seen in patients undergoing cardiac procedures. Nevertheless, little is known about the histopathological features of new-onset postoperative AVB prior to the clinical manifestation and its prognostic impact. Purpose This study explores the association of first-degree AVB in ECG and postoperative outcome of patients with either preoperative or a new-onset AVB. Furthermore, histopathological features were analyzed to distinguish the characteristics between preoperative and postoperative AVBs compared to no AVB. Methods CAREBANK is a prospective study with atrial biopsies obtained at the time of open-heart cardiac surgery and long-term follow-up focusing on the adverse events. We analyzed preoperative as well as postoperative ECGs derived after index hospitalization (1-18mo) in patients undergoing CABG. The definition of first-degree AVB was PR-interval ≥200ms. The main outcome of interest was follow-up mortality. Histopathological analysis was used to assess the amount of fibrosis, cardiomyocytes, number of nuclei and macrophages. Results Median follow up time was 4.0 (IQR 2.7 – 5.0) years. First-degree AVB was found in 84/373 (22.5%) preoperative ECGs. Altogether 25/289 (8.7%) cases where ECG was available (after excluding preop AVB, atrial fibrillation) developed first-degree AVB after index hospitalization. New-onset first-degree AVB was associated with increased mortality (aHR 4.033 (95-CI% 1.019–15.965, p=0.047). In atrial histopathological analysis, area covered by cardiomyocytes (p=0.033) as well as area covered by nuclei (p=0.047) were smaller in those with new-onset AVB after surgery, but not in those with preoperative first-degree AVB (p=0.692 and p=0.384) as compared with controls, respectively. Similarly, the total area of fibrosis was greater in those with preoperative first-degree AVB (p<0.001), but not in those with postoperative new-onset AVB (p=0.244). When compared with controls, share of CD68 positive macrophages was similar (p=0.073), but anti-inflammatory CD206 positive M2 macrophages were absent in patients with new-onset AVB (p=0.042). Conclusion Patients with new-onset AVB after CABG have increased mortality in the long-term compared to those without. Histopathology identifies marked differences in macrophage populations between those with and without new-onset AVB.

Multiomics identification of ALDH9A1 as a crucial immunoregulatory molecule involved in calcific aortic valve disease

Mitochondrial dysfunction and immune cell infiltration play crucial yet incompletely understood roles in the pathogenesis of calcific aortic valve disease (CAVD). This study aimed to identify immune-related mitochondrial genes critical to the pathological process of CAVD using multiomics approaches. The CIBERSORT algorithm was employed to evaluate immune cell infiltration characteristics in CAVD patients. An integrative analysis combining weighted gene coexpression network analysis (WGCNA), machine learning, and summary data-based Mendelian randomization (SMR) was performed to identify key mitochondrial genes implicated in CAVD. Spearman’s rank correlation analysis was also performed to assess the relationships between key mitochondrial genes and infiltrating immune cells. Compared with those in normal aortic valve tissue, an increased proportion of M0 macrophages and resting memory CD4 T cells, along with a decreased proportion of plasma cells and activated dendritic cells, were observed in CAVD patients. Additionally, eight key mitochondrial genes associated with CAVD, including PDK4, LDHB, SLC25A36, ALDH9A1, ECHDC2, AUH, ALDH2, and BNIP3, were identified through the integration of WGCNA and machine learning methods. Subsequent SMR analysis, incorporating multiomics data, such as expression quantitative trait loci (eQTLs) and methylation quantitative trait loci (mQTLs), revealed a significant causal relationship between ALDH9A1 expression and a reduced risk of CAVD. Moreover, ALDH9A1 expression was inversely correlated with M0 macrophages and positively correlated with M2 macrophages. These findings suggest that increased ALDH9A1 expression is significantly associated with a reduced risk of CAVD and that it may exert its protective effects by modulating mitochondrial function and immune cell infiltration. Specifically, ALDH9A1 may contribute to the shift from M0 macrophages to anti-inflammatory M2 macrophages, potentially mitigating the pathological progression of CAVD. In conclusion, ALDH9A1 represents a promising molecular target for the diagnosis and treatment of CAVD. However, further validation through in vivo and n vitro studies is necessary to confirm its role in CAVD pathogenesis and therapeutic potential.

Preparation of a chitosan/polyvinyl alcohol-based dual-network hydrogel for use as a potential wound-healing material for the sustainable release of drugs

Treating chronic wounds poses significant challenges in clinical medicine due to bacterial infection, reactive oxygen species (ROS) accumulation, and excessive inflammation. This study aimed to address these issues by developing a wound dressing with antibacterial, antioxidant, and anti-inflammatory properties. Chitosan was functionally modified with acrolein to covalently bind to epigallocatechin gallate (EGCG), enabling a high EGCG load. Subsequently, polyvinyl alcohol (PVA) and EGCG-modified chitosan were crosslinked to prepare a new double-network hydrogel with added cysteine (CSAEC/P50). CSAEC/P50 demonstrated optimal mechanical properties (low swelling rate, high water retention, and optimal flexibility), low hemolysis, high coagulation properties, and antibacterial and antioxidant activities. Cell scratch tests indicated that CSAEC/P50 can promote NIH3T3 cell migration. Immunofluorescence results showed that CSAEC/P50 promoted the transformation of proinflammatory M1 macrophages to anti-inflammatory M2 macrophages. These findings suggest that CSAEC/P50 has significant potential for use in wound dressing applications.

The Role of Macrophages in Airway Disease Focusing on Porcine Reproductive and Respiratory Syndrome Virus and the Treatment with Antioxidant Nanoparticles.

Lung macrophage cells play a critical role in various lung diseases, and their state can change depending on the progression of the disease by inducing either an inflammatory or anti-inflammatory state. In this review, the potential therapeutic effects of treatment with antioxidant nanoparticles in air-borne diseases focusing on porcine reproductive and respiratory virus (PRRSV), considering reactive oxygen species (ROS) as one of the factors that regulate M1 and M2 macrophages in the inflammatory and anti-inflammatory states, respectively, was described. In addition, the author examines the status of protein structure research on CD163 (one of the markers of anti-inflammatory M2 macrophages) in human and veterinary lung diseases.

Lactobacillus paracasei JY062 and its exopolysaccharide enhance the intestinal barrier through macrophage polarization and Th17/Treg cell balance

Ulcerative colitis (UC) is an immune-mediated intestinal disease without a comprehensive cure, and the alleviation of UC has become an urgent problem. The results showed that JY062 with its EPS group (JEC) alleviated the intestinal barrier damage caused by LPS. After JEC intervention on Caco-2 cells, resulted in upregulation of ZO-1, Claudin-1, Occludin and MUC2 transcript levels and decreased mRNA expression of Claudin-2 (p < 0.05). JEC effectively attenuated the inflammatory response in UC mice and restoration of immunoglobulin levels (IgG, IgM and IgA), which resulted in shortening and swelling of the colon, disappearance of goblet cells, infiltration of inflammatory cells and mucosal damage were alleviated in mice. Similarly, changes in the expression of MUC2 and tight junction proteins after JEC intervention also occurred in UC mice. Administration of JEC significantly inhibited the differentiation of pro-inflammatory Th17 cells in the thymus and peripheral blood, promoted the differentiation of CD4+ T cells to Treg cells, and effectively regulated DSS-induced macrophage imbalance, which was manifested by the polarization of pro-inflammatory M1 macrophages to anti-inflammatory M2 macrophages. This study clearly demonstrates that JEC could significantly prevent intestinal barrier on DSS-induced experimental colitis and could be applied as a potential symbiotic strategy to assist in the alleviation of UC.

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.

Evidence for a Pro-Inflammatory State of Macrophages from Non-Obese Type-2 Diabetic Goto-Kakizaki Rats

Obesity causes insulin resistance (IR) through systemic low-grade inflammation and can lead to type 2 diabetes mellitus (T2DM). However, the mechanisms that cause IR and T2DM in non-obese individuals are unclear. The Goto-Kakizaki (GK) rat develops IR spontaneously and is a model of non-obese T2DM. These rats exhibit hyperglycemia beginning at weaning and exhibit lower body mass than control Wistar rats. Herein, we tested the hypothesis that macrophages of GK rats are permanently in a pro-inflammatory state, which may be associated with a systemic inflammation condition that mimics the pathogenesis of obesity-induced T2DM. Using eighteen-week-old GK and control Wistar rats, we investigated the proportions of M1 (pro-inflammatory) and M2 (anti-inflammatory) macrophages isolated from the peritoneal cavity. Additionally, the production of inflammatory cytokines and reactive oxygen species (ROS) in cultured macrophages under basal and stimulated conditions was assessed. It was found that phorbol myristate acetate (PMA) stimulation increased GK rat macrophage ROS production 90-fold compared to basal levels. This response was also three times more pronounced than in control cells (36-fold). The production of pro-inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α), tended to be upregulated in cultured macrophages from GK rats under basal conditions. Macrophages from GK rats produced 1.6 times more granulocyte-macrophage colony-stimulating factor (GM-CSF), 1.5 times more monocyte chemoattractant protein-1 (MCP-1) and 3.3 times more TNF-α than control cells when stimulated with lipopolysaccharide (LPS) (p = 0.0033; p = 0.049; p = 0.002, respectively). Moreover, compared to control cells, GK rats had 60% more M1 (p = 0.0008) and 23% less M2 (p = 0.038) macrophages. This study is the first to report macrophage inflammatory reprogramming towards a pro-inflammatory state in GK rats.

The role of erythropoietin-loaded hydrogel versus adipose derived stem cell secretome in the regeneration of tongue defects

BackgroundTongue defects have several etiologies and significantly affect the quality of life. This study was conducted to compare the regenerative potential of erythropoietin (EPO)-loaded hydrogel and adipose derived stem cell (ADSC) secretome on tongue dorsum defects focusing on the role of anti-inflammatory M2 macrophage phenotype.MethodsRats were subjected to induction of mechanical circular defects on the dorsal surface of the tongue, then divided into three groups; Group I (control): received 0.1 ml phosphate buffered saline, Group II (EPO): received 5000 U/kg EPO-hydrogel, and Group III (ADSC-Secretome): received 0.1 ml ADSC-Secretome. Treatments were injected circumferentially around wound margins after induction. Seven and fourteen days after treatment, specimens were obtained and processed for histological and immunohistochemical staining followed by the relevant histomorphometric and statistical analyses.ResultsSeven days after treatment, groups II and III presented defects with some epithelial regeneration at the lateral margins, while the center of the defect showed granulation tissue with much inflammatory cells. The base of the defects showed some muscle fibers and new blood vessels, however group III showed more enhanced neovascularization. Fourteen days after therapeutic intervention, group II defects were completely covered with epithelium showing a thin keratin layer with regular rete pegs interdigitating with the underlying connective tissue papillae, but tongue papillae were not restored. Group III expressed much better healing with developing filiform papillae. The connective tissue showed more vascularity and well-arranged muscle bundles. Both treated groups showed a significant decrease in defect depth and significant increase in anti-inflammatory macrophages compared to the control group at both time intervals, however there was no significant difference between the two treated groups.ConclusionBoth treatments showed promising and comparable results in the treatment of tongue defects reducing inflammation and restoring tongue histological architecture with significant upregulation of M2 macrophage.

Activation of G Protein-Coupled Estrogen Receptor 1 (GPER) Attenuates Obesity-Induced Asthma by Switching M1 Macrophages to M2 Macrophages.

The prevalence of obesity-induced asthma increases in women after menopause. We hypothesized that the increase in obese asthma in middle-aged women results from estrogen loss. In particular, we focused on the acute action of estrogen through the G protein-coupled estrogen receptor 1 (GPER), previously known as GPR30. We investigated whether GPER activation ameliorates obesity-induced asthma with a high-fat diet (HFD) using G-1, the GPER agonist, and G-36, the GPER antagonist. Administration of G-1 (0.5 mg/kg) suppressed HFD-induced airway hypersensitivity (AHR), and increased immune cell infiltration, whereas G-36 co-treatment blocked it. Histological analysis showed that G-1 treatment inhibited HFD-induced inflammation, fibrosis, and mucus hypersecretion in a GPER-dependent manner. G-1 inhibited the HFD-induced rise in the mRNA levels of pro-inflammatory cytokines in the gonadal white adipose tissue and lungs, whereas G-36 co-treatment reversed this effect. G-1 increased anti-inflammatory M2 macrophages and inhibited the HFD-induced rise in pro-inflammatory M1 macrophages in the lungs. In addition, G-1 treatment reversed the HFD-induced increase in leptin expression and decrease in adiponectin expression in the lungs and gonadal white adipose tissue. The results suggest that activation of GPER could be a therapeutic option for obesity-induced asthma.

BP1003 Decreases STAT3 Expression and Its Pro-Tumorigenic Functions in Solid Tumors and the Tumor Microenvironment.

Overexpression and aberrant activation of signal transducer and activator of transcription 3 (STAT3) contribute to tumorigenesis, drug resistance, and tumor-immune evasion, making it a potential cancer therapeutic target. BP1003 is a neutral liposome incorporated with a nuclease-resistant P-ethoxy antisense oligodeoxynucleotide (ASO) targeting the STAT3 mRNA. Its unique design enhances BP1003 stability, cellular uptake, and target affinity. BP1003 efficiently reduces STAT3 expression and enhances the sensitivity of breast cancer cells (HER2+, triple negative) and ovarian cancer cells (late stage, invasive ovarian cancer) to paclitaxel and 5-fluorouracil (5-FU) in both 2D and 3D cell cultures. Similarly, ex vivo and in vivo patient-derived models of pancreatic ductal adenocarcinoma (PDAC) show reduced tissue viability and tumor volume with BP1003 and gemcitabine combination treatments. In addition to directly affecting tumor cells, BP1003 can modulate the tumor microenvironment. Unlike M1 differentiation, monocyte differentiation into anti-inflammatory M2 macrophages is suppressed by BP1003, indicating its potential contribution to immunotherapy. The broad anti-tumor effect of BP1003 in numerous preclinical solid tumor models, such as breast, ovarian, and pancreatic cancer models shown in this work, makes it a promising cancer therapeutic.

Omega-3 fatty acids prevent gestational diabetes mellitus via modulation of lipid metabolism.

The incidence rate of gestational diabetes mellitus (GDM) remains high among pregnant women in the second trimester of pregnancy. However, the main clinical approach to alleviate the symptoms of GDM is to control the diet. Our study explored the therapeutic effects of omega-3 fatty acids (ω-3 FAs) on GDM at the cellular and animal levels. We found that ω-3 FAs can promote the transformation of M0 macrophages into anti-inflammatory M2 macrophages. The transformed M2 macrophages promoted β-oxidation and reduced hepatocyte lipid synthesis (P < 0.05), thereby promoting hepatic function and preventing the excessive accumulation of lipid droplets in the hepatocyte cell line HepG2. Supplementation of ω-3 FAs in pregnant GDM mice significantly reduced fasting blood glucose levels, glucose tolerance test, and insulin tolerance test indices, and lipid accumulation in the liver and effectively prevented the occurrence of liver fibrosis (P < 0.05). These therapeutic effects may be mediated through the anti-inflammatory effects of ω-3 FAs (P < 0.05). ω-3 FAs also had positive effects on the offspring of pregnant GDM mice, as demonstrated by reduced birth mortality and improved glycemic stabilization (P < 0.05). In conclusion, this study provides a possible translational medicine strategy for the treatment of GDM.

Dissolvable microneedle patch enables local delivery of immunomodulatory microparticles containing bifunctional molecules for periodontal tissue regeneration

Periodontitis is initiated by dysbiosis of the oral microbiome. Pathogenic bacteria elicit ineffective immune responses, which damage surrounding tissues and lead to chronic inflammation. Although current treatments typically aim for microbial eradication, they fail to address the significance of immune cell reactions in disease progression. Here, we searched for small molecules as drug candidates and identified a bifunctional antibiotic, azithromycin (AZM), that not only inhibits bacterial growth but also modulates immune cells to suppress inflammation. We further engineered a dissolvable microneedle patch loaded with biodegradable microparticles for local and painless delivery of AZM to the gingival tissues. Inflammatory cytokines were decreased while anti-inflammatory cytokines and M2 macrophage were increased with AZM treatments in vitro. In vivo delivery of the AZM-loaded microneedle patch demonstrated the same effects on cytokine secretion and the promotion of tissue healing and bone regeneration. In addition, microparticles containing anti-inflammatory interleukin-4 alone or in combination with separately-formulated AZM microparticles, had similar or slightly enhanced therapeutic outcomes respectively. The bimodal action of AZM obviates the necessity for separate antibacterial and immunomodulatory agents, providing a practical and streamlined approach for clinical treatment. Our findings also demonstrate the therapeutic efficacy of microparticles delivery into the soft tissues by a minimally invasive and fast-degrading microneedle patch and offer a novel therapeutic approach for the treatment of periodontitis and other diseases through immunomodulation.Graphical

Probiotic treatment with viable α-galactosylceramide-producing Bacteroides fragilis reduces diabetes incidence in female nonobese diabetic mice.

We aimed to investigate whether alpha-galactosylceramide (α-GalCer)-producing Bacteroides fragilis could induce natural killer T (NKT) cells in nonobese diabetic (NOD)mice and reduce their diabetes incidence. Five-week-old female NOD mice were treated orally with B. fragilis, and islet pathology and diabetes onset were monitored. Immune responses were analyzed by flow cytometry and multiplex technology. Effects of ultraviolet (UV)-killed α-GalCer-producing B. fragilis and their culture medium on invariant NKT (iNKT) cells were tested ex vivo on murine splenocytes, and the immunosuppressive capacity of splenocytes from B. fragilis-treated NOD mice were tested by adoptive transfer to nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice. B. fragilis reduced the diabetes incidence from 69% to 33% and the percent of islets with insulitis from 40% to 7%, which doubled the serum insulin level compared with the vehicle-treated control mice. Furthermore, the early treatment reduced proinflammatory mediators in the serum, whereas the proportion of CD4+ NKT cell population was increased by 33%. B. fragilis growth media stimulated iNKT cells and anti-inflammatory M2 macrophages ex vivo in contrast to UV-killed bacteria, which had no effect, strongly indicating an α-GalCer-mediated effect. Adoptive transfer of splenocytes from B. fragilis-treated NOD mice induced a similar diabetes incidence as splenocytes from untreated NOD mice. B. fragilis induced iNKT cells and M2 macrophages and reduced type 1 diabetes in NOD mice. The protective effect seemed to be more centered on gut-pancreas interactions rather than a systemic immunosuppression. B. fragilis should be considered for probiotic use in individuals at risk of developing type 1 diabetes.

Aucubin suppresses TLR4/NF-κB signalling to shift macrophages toward M2 phenotype in glucocorticoid-associated osteonecrosis of the femoral head.

In this study, we investigated whether the ability of aucubin to mitigate the pathology of GONFH involves suppression of TLR4/NF-κB signalling and promotion of macrophage polarization to an M2 phenotype. In necrotic bone tissues from GONFH patients, we compared levels of pro-inflammatory M1 macrophages and anti-inflammatory M2 macrophages as well as levels of TLR4/NF-κB signalling. In a rat model of GONFH, we examined the effects of aucubin on these parameters. We further explored its mechanism of action in a cell culture model of M1 macrophages. Necrotic bone tissues from GONFH patients contained a significantly increased macrophage M1/M2 ratio, and higher levels of TLR4, MYD88 and NF-κB p65 than bone tissues from patients with hip osteoarthritis. Treating GONFH rats with aucubin mitigated bone necrosis and demineralization as well as destruction of trabecular bone and marrow in a dose-dependent manner, based on micro-computed tomography. These therapeutic effects were associated with a decrease in the overall number of macrophages, decrease in the proportion of M1 macrophages, increase in the proportion of M2 macrophages, and downregulation of TLR4, MYD88 and NF-κB p65. These effects invivo were confirmed by treating cultures of M1 macrophage-like cells with aucubin. Aucubin mitigates bone pathology in GONFH by suppressing TLR4/NF-κB signalling to shift macrophages from a pro- to anti-inflammatory phenotype.

CDK8/19 inhibitor enhances arginase-1 expression in macrophages via STAT6 and p38 MAPK activation

Macrophages polarize into alternatively activated M2 macrophages through interleukin (IL)-4, and they express high levels of arginase-1, which promotes anti-inflammatory responses. Several studies have confirmed the anti-inflammatory effects of cyclin-dependent kinase (CDK) 8/19 inhibition, and hence, numerous CDK8/19 inhibitors, such as BRD6989, have been developed. However, the effects of CDK8/19 inhibitors on arginase-1 expression in macrophages have not yet been elucidated. This study investigated the effects of CDK8/19 inhibitor on arginase-1 expression in IL-4-activated macrophages. The results showed that BRD6989 increased arginase-1 expression transcriptionally in murine peritoneal macrophages and the murine macrophage cell line RAW264.7 in an IL-4-dependent manner. In addition, the results indicated that BRD6989 enhances signal transducer and activator of transcription (STAT) 6 phosphorylation. Meanwhile, BRD6989 exhibited the capability to activate p38 mitogen-activated protein kinase (MAPK） even in the absence of IL-4 stimulation. Moreover, we observed that a p38 MAPK inhibitor suppressed the BRD6989-induced increase in arginase-1 expression. Besides, BRD6989 increased the surface expression of CD206, an M2 macrophage marker. Thus, this study demonstrated for the first time that CDK8/19 inhibition increases arginase-1 expression, suggesting that this mechanism involves the activation of STAT6 and p38 MAPK. This finding implies that CDK8/19 inhibition may facilitate the production of anti-inflammatory M2 macrophages.

Black Phosphorus Nanosheets-Based Hydrogel for Efficient Bacterial Inhibition and Accelerating Wound Healing.

With the swift evolution of multidrug-resistant bacteria resulting from the intense and inappropriate use of antibiotics, there is a pressing need for innovative solutions. In this study, a thermosensitive hydrogel was developed for efficient bacterial inhibition and promotion of wound healing. The antibacterial chitosan (CS) thermosensitive hydrogel, cross-linked with two-dimensional photothermal nanomaterial black phosphorus (BP) nanosheets through electrostatic interactions, effectively encapsulates and sustains the release of angiogenic drug deferoxamine mesylate (DFO). This facilitates the acceleration of re-epithelialization and neovascularization by enhancing cell migration and proliferation. Following near-infrared (NIR) treatment, this hydrogel demonstrates rapid eradication of the most common multidrug-resistant bacteria encountered in clinical settings, achieved through physical disruption of bacterial membranes and photothermal therapies. Noteworthy is the significant upregulation of IL-19 expression via STAT3 signaling pathways by the BP/CS-DFO hydrogel in a full-thickness wound model. This results in the polarization of the anti-inflammatory M2 macrophage phenotype, altering the microenvironment to a pro-healing state and enhancing extracellular matrix deposition and blood vessel formation. In conclusion, the BP/CS-DFO hydrogel shows immense promise as a potential clinical candidate for wound healing and antimicrobial therapy. Its innovative design and multifunctional capabilities position it as a valuable asset in combating antibiotic resistance and enhancing efficiency in wound healing.

Injectable immunoregulatory hydrogels sequentially drive phenotypic polarization of macrophages for infected wound healing

Regulating macrophage phenotypes to reconcile the conflict between bacterial suppression and tissue regeneration is ideal for treating infectious skin wounds. Here, an injectable immunoregulatory hydrogel (SrmE20) that sequentially drives macrophage phenotypic polarization (M0 to M1, then to M2) was constructed by integrating anti-inflammatory components and proinflammatory solvents. In vitro experiments demonstrated that the proinflammatory solvent ethanol stabilized the hydrogel structure, maintained the phenolic hydroxyl group activity, and achieved macrophages' proinflammatory transition (M0 to M1) to enhance antibacterial effects. With ethanol depletion, the hydrogel's cations and phenolic hydroxyl groups synergistically regulated macrophages' anti-inflammatory transition (M1 to M2) to initiate regeneration. In the anti-contraction full-thickness wound model with infection, this hydrogel effectively eliminated bacteria and even achieved anti-inflammatory M2 macrophage accumulation at three days post-surgery, accelerated angiogenesis and collagen deposition. By sequentially driving macrophage phenotypic polarization, this injectable immunoregulatory hydrogel will bring new guidance for the care and treatment of infected wounds.