Circular RNA P4HB promotes glycolysis and tumor progression by binding with PKM2 in lung adenocarcinoma

BACKGROUND

Emerging evidence indicates that circular RNAs (circRNAs) play vital roles in tumor progression, including lung adenocarcinomas (LUAD). However, the mechanisms by which circRNAs promote the progression of LUAD still require further investigation.

METHODS

Quantitative real-time PCR was performed to detect the expression of circP4HB in LUAD tissues and cells. Then, Kaplan-Meier analysis was used to determine the prognostic value of circP4HB expression. We employed RNA pull-down, RNA immunoprecipitation, mass spectrometry, cells fraction, glucose consumption, lactate production, pyruvate kinase M2 (PKM2) activity, and macrophage polarization assays to uncover the underlying mechanisms of circP4HB in LUAD.

RESULTS

We found that circP4HB is upregulated in LUAD tissues and correlated with advanced TNM stages and lymph node metastasis. LUAD patients with high circP4HB expression had poor prognoses. Functionally, circP4HB promoted LUAD progression in vivo and in vitro. Upregulated circP4HB increased glucose consumption, lactate production and accelerated aerobic glycolysis in LUAD cells. Mechanically, circP4HB mainly accumulated in the cytoplasm of LUAD cells and bound with PKM2 and subsequently upregulating PKM2 enzymatic activity by increasing its tetramer formation. Additionally, circP4HB promoted M2 macrophage phenotype shift via targeting PKM2. Finally, rescue assays further confirmed that circP4HB could promote LUAD cell progression through its interaction with PKM2.

CONCLUSION

These results demonstrate that circP4HB could promote LUAD progression, indicating circP4HB might be a potential therapeutic target of LUAD.

A hydrogel reservoir as a self-contained nucleus pulposus cell delivery vehicle for immunoregulation and repair of degenerated intervertebral disc

The strategies for modulating the local inflammatory microenvironment to inhibit intervertebral disc degeneration (IVDD) have garnered significant interest in recent years. In this study, we developed a "self-contained" injectable hydrogel capable of storing Mg2+ while carrying nucleus pulposus (NP) cells, with the aim of inhibiting IVDD through immunoregulation. The hydrogel consists of sodium alginate (SA), poly(N-isopropylacrylamide) (PNIPAAm), silicate ceramics (SC), and NP cells. When injected into the NP site, PNIPAAm gelates instantly under body temperature, forming an interpenetrating network (IPN) hydrogel with SA. Ca2+ released from the SC can crosslink the SA in situ, forming a SA/PNIPAAm hydrogel with an interpenetrating network (IPN) encapsulating the NP cells. Moreover, inside the hydrogel, Mg2+ released from SC are effectively encapsulated and maintained at a desirable concentration. These Mg2+ facilitates the local cell matrix synthesis and promotes immunomodulation (upregulating M2 / downregulating M1 macrophage polarization), thus inhibiting the IVDD progression. The proposed hydrogel has biocompatibility and is shown to enhance the expression of collagen II (COL II) and aggrecan. The potential of the injectable hydrogel in IVD repair has also been successfully demonstrated by in vivo studies. STATEMENT OF SIGNIFICANCE.

Aspect ratio-dependent dual-regulation of the tumor immune microenvironment against osteosarcoma by hydroxyapatite nanoparticles

Accumulating studies demonstrated that hydroxyapatite nanoparticles (HANPs) showed a selective anti-tumor effect, making them a good candidate for osteosarcoma (OS) treatment. However, the capacity of HANPs with different aspect ratios to regulate tumor immune microenvironment (TIM) was scarcely reported before. To explore it, the three HANPs with aspect ratios from 1.86 to 6.25 were prepared by wet chemical method. After a 24 or 72 h-exposure of OS UMR106 cells or macrophages to the nanoparticles, the tumor cells exhibited immunogenic cell death (ICD) indicated by the increased production of calreticulin (CRT), adenosine triphosphate (ATP) and high mobility group box 1 (HMGB1), and macrophages were activated with the release of pro-inflammatory cytokines. Next, the beneficial crosstalk between tumor cells and macrophages generated in the presence of HANPs for improved anti-tumor immunity activation. In the OS-bearing cognate rat model, HANPs inhibited OS growth, which was positively correlated with CRT and HMGB1 expression, and macrophage polarization in the tumor tissues. Additionally, HANPs promoted CD8+ T cell infiltration into the tumor and systemic dendritic cell maturation. Particularly, HANPs bearing the highest aspect ratio exhibited the strongest immunomodulatory and anti-tumor function. This study suggested the potential of HANPs to be a safe and effective drug-free nanomaterial to control the TIM for OS therapy. STATEMENT OF SIGNIFICANCE: Emerging studies demonstrated that hydroxyapatite nanoparticles (HANPs) inhibited tumor cell proliferation and tumor growth. However, the underlying anti-tumor mechanism still remains unclear, and the capacity of HANPs without any other additive to regulate tumor immune microenvironment (TIM) was scarcely reported before. Herein, we demonstrated that HANPs, in an aspect ratio-dependent manner, showed the potential to delay the growth of osteosarcoma (OS) and to regulate TIM by promoting the invasion of CD8+ T cells and F4/80+ macrophages, and inducing immunogenic cell death (ICD) in tumors. This work revealed the new molecular mechanism for HANPs against OS, and suggested HANPs might be a novel ICD inducer for OS treatment.

Macrophage polarization in tissue fibrosis

Fibrosis can occur in all major organs with relentless progress, ultimately leading to organ failure and potentially death. Unfortunately, current clinical treatments cannot prevent or reverse tissue fibrosis. Thus, new and effective antifibrotic therapeutics are urgently needed. In recent years, a growing body of research shows that macrophages are involved in fibrosis. Macrophages are highly heterogeneous, polarizing into different phenotypes. Some studies have found that regulating macrophage polarization can inhibit the development of inflammation and cancer. However, the exact mechanism of macrophage polarization in different tissue fibrosis has not been fully elucidated. This review will discuss the major signaling pathways relevant to macrophage-driven fibrosis and profibrotic macrophage polarization, the role of macrophage polarization in fibrosis of lung, kidney, liver, skin, and heart, potential therapeutics targets, and investigational drugs currently in development, and hopefully, provide a useful review for the future treatment of fibrosis.

Advances in the study of macrophage polarization in inflammatory immune skin diseases

When exposed to various microenvironmental stimuli, macrophages are highly plastic and primarily polarized into the pro-inflammatory M1-type and the anti-inflammatory M2-type, both of which perform almost entirely opposing functions. Due to this characteristic, macrophages perform different functions at different stages of immunity and inflammation. Inflammatory immune skin diseases usually show an imbalance in the M1/M2 macrophage ratio, and altering the macrophage polarization phenotype can either make the symptoms worse or better. Therefore, this review presents the mechanisms of macrophage polarization, inflammation-related signaling pathways (JAK/STAT, NF-κB, and PI3K/Akt), and the role of both in inflammatory immune skin diseases (psoriasis, AD, SLE, BD, etc.) to provide new directions for basic and clinical research of related diseases.

Bioinspired nanovesicles released from injectable hydrogels facilitate diabetic wound healing by regulating macrophage polarization and endothelial cell dysfunction

Wound healing is one of the major global health concerns in diabetic patients. Overactivation of proinflammatory M1 macrophages could lead to delayed wound healing in diabetes. 4-octyl itaconate (4OI), a derivative of the metabolite itaconate, has aroused growing interest recently on account of its excellent anti-inflammatory properties. Cell membrane coating is widely regarded as a novel biomimetic strategy to deliver drugs and inherit properties derived from source cells for biomedical applications. Herein, we fused induced pluripotent stem cell-derived endothelial cell (iEC) membrane together with M1 type macrophage membrane to construct a hybrid membrane (iEC-M) camouflaged 4OI nanovesicles (4OI@iEC-M). Furthermore, bioinspired nanovesicles 4OI@iEC-M are incorporated into the injectable, multifunctional gelatin methacryloyl hydrogels for diabetic wound repair and regeneration. In our study, bioinspired nanovesicles could achieve dual-targeted deliver of 4OI into both M1 macrophages and endothelial cells, thereby promoting macrophage polarization and protecting endothelial cells. With the synergistically anti-inflammatory and immunoregulative effects, the bioinspired nanovesicles-loaded hydrogels could facilitate neovascularization and exhibit superior diabetic wound repair and regeneration. Taken together, this study might provide a novel strategy to facilitate diabetic wound healing, thereby reducing limb amputation and mortality of diabetes.

In situ sprayed hydrogels containing resiquimod-loaded liposomes reduce chronic osteomyelitis recurrence by intracellular bacteria clearance

At present, surgical debridement and systematic administration of antibiotics represent the mainstay of treatment for chronic osteomyelitis. However, it is now understood that Staphylococcus aureus (S. aureus) can survive within excessively polarized M2 macrophages and evade antibiotics, accounting for the high recurrence of chronic osteomyelitis. Effective treatments for intracellular infection have rarely been reported. Herein, we designed an in situ sprayed liposomes hydrogels spray with macrophage-targeted effects and the ability to reverse polarization and eradicate intracellular bacteria to reduce the recurrence of osteomyelitis. Resiquimod (R848)-loaded and phosphatidylserine (PS)-coating nanoliposomes were introduced into fibrinogen and thrombin to form the PSL-R848@Fibrin spray. Characterization and phagocytosis experiments were performed to confirm the successful preparation of the PSL-R848@Fibrin spray. Meanwhile, in vitro cell experiments validated its ability to eliminate intracellular S. aureus by reprogramming macrophages from the M2 to the M1 phenotype. Additionally, we established a chronic osteomyelitis rat model to simulate the treatment and recurrence process. Histological analysis demonstrated a significant increase in M1 macrophages and the elimination of intracellular bacteria. Imaging revealed a significant decrease in osteomyelitis recurrence. Overall, the liposome hydrogels could target macrophages to promote antibacterial properties against intracellular infection and reduce the recurrence of chronic osteomyelitis, providing the foothold for improving the outcomes of this patient population. STATEMENT OF SIGNIFICANCE: Chronic osteomyelitis remains a high recurrence although undergoing traditional treatment of debridement and antibiotics. S. aureus can survive within the excessively polarized M2 macrophages to evade the effects of antibiotics. However, few studies have sought to investigate effective intracellular bacteria eradication. Herein, we designed a macrophage-targeted R848-containing liposomes fibrin hydrogels spray (PSL-R848@Fibrin) that can reprogram polarization of macrophages and eradicate intracellular bacteria for osteomyelitis treatment. With great properties of rapid gelation, strong adhesion, high flexibility and fit-to-shape capacity, the facile-operated immunotherapeutic in-situ-spray fibrin hydrogels exhibited huge promise of reversing polarization and fighting intracellular infections. Importantly, we revealed a hitherto undocumented treatment strategy for reducing the recurrence of chronic osteomyelitis and potentially improving the prognosis of chronic osteomyelitis patients.

The microRNA-4766/VEGFA axis mediates macrophage M2-type polarization to inhibit colorectal cancer proliferation and migration

OBJECTIVE

To investigate the miR-4766/VEGFA axis in regulating M2-type macrophage polarization under hypoxia and its effect on the proliferation and migration of colorectal cancer (CRC) cells.

METHODS

The differentially expressed genes (DEGs) in macrophages before and after hypoxia treatment in the dataset GSE154427 were analyzed. microRNA (miR)-4766 and VEGFA were selected as the research objects and then detected for mRNA expression and protein level using qRT-PCR and Western blot, respectively. The expression levels of M2 macrophage markers such as CD206, CD163, and ARG1 were detected to determine the M2-type macrophage polarization. The targeted binding of miR-4766 to VEGFA was verified using Dual-luciferase reporter gene assay. CCK-8 and Transwell assays were performed, respectively, to detect the capacity of cells to proliferate and migrate. IL-10 and TGF-β levels in the conditioned medium were detected using ELISA.

RESULTS

miR-4766 was upregulated, and VEGFA was downregulated in hypoxia-treated macrophages. miR-4766 inhibited, while VEGFA promoted the polarization of M2-type macrophages. miR-4766 targeted and negatively regulated VEGFA. miR-4766 inhibited the polarization of M2-type macrophages and then suppressed CRC cell proliferation and migration via targeting VEGFA.

CONCLUSION

Restoring miR-4766 expression to inhibit VEGFA expression promised to be a potential strategy to suppress CRC development.

M2 macrophage-derived exosomes promote diabetic fracture healing by acting as an immunomodulator

Diabetes mellitus is a chronically inflamed disease that predisposes to delayed fracture healing. Macrophages play a key role in the process of fracture healing by undergoing polarization into either M1 or M2 subtypes, which respectively exhibit pro-inflammatory or anti-inflammatory functions. Therefore, modulation of macrophage polarization to the M2 subtype is beneficial for fracture healing. Exosomes perform an important role in improving the osteoimmune microenvironment due to their extremely low immunogenicity and high bioactivity. In this study, we extracted the M2-exosomes and used them to intervene the bone repair in diabetic fractures. The results showed that M2-exosomes significantly modulate the osteoimmune microenvironment by decreasing the proportion of M1 macrophages, thereby accelerating diabetic fracture healing. We further confirmed that M2-exosomes induced the conversion of M1 macrophages into M2 macrophages by stimulating the PI3K/AKT pathway. Our study offers a fresh perspective and a potential therapeutic approach for M2-exosomes to improve diabetic fracture healing.

Cuyun Recipe ameliorates pregnancy loss by regulating macrophage polarization and hypercoagulable state during the peri-implantation period in an ovarian hyperstimulation mouse model

BACKGROUND

The Chinese herbal prescription Cuyun Recipe (CYR) has been widely used to treat clinical infertility and has shown good efficacy. Animal experiments have shown that CYR can promote implantation in mice, however, the exact mechanism underlying the implantation has not been elucidated.

PURPOSE

To investigate the effect and mechanism of CYR on regulating macrophage polarization and hypercoagulability during the peri-implantation period in mice with ovarian hyperstimulation.

METHODS

An ovarian hyperstimulation mouse model was developed, followed by treatment with CYR. Mice were sacrificed on day (D)4.5, D6, or D8 of gestation. The number of implantation sites, the pathological changes of the uterus and ovaries were assessed. The polarization of monocytes/macrophages in the spleen and endometrium, the expression and localization of cytokines were further detected. Furthermore, analyses of hypercoagulable state of the blood were also performed.

RESULTS

Treatment with CYR increased the average number of implantation sites, promoted angiogenesis in endometrial, and regulated monocytes/macrophages and the cytokine levels. Moreover, CYR downregulated the overexpression of D-dimer and fgl2 after ovarian hyperstimulation.

CONCLUSION

CYR facilitates embryo implantation by alleviating ovarian hyperstimulation, promoting endometrial decidualization and angiogenesis, regulating macrophage polarization, and reversing the hypercoagulable state of the blood.

rFSAV promotes Staphylococcus aureus-infected bone defect healing via IL-13- mediated M2 macrophage polarization

Staphylococcus aureus (S. aureus) contamination commonly occurs in orthopedic internal fixation operations, leading to a delayed healing of the defected bone tissue. However, antibiotic treatments are ineffective in dealing with S. aureus bone infections due to the rise in multiple antimicrobial resistances. Here, we reported the protective effects of a recombinant five-antigen S. aureus vaccine (rFSAV) in an S. aureus infected bone defect model. In this study, we found the number of M2 macrophages markedly increased in the defect site and played a critical role in the healing of defected bone mediated by rFSAV. Mechanistically, rFSAV mediated increased level of IL-13 in bone defect site predominant M2 macrophage polarization. In summary, our study reveals a key role of M2 macrophage polarization in the bone regeneration process in S. aureus infection induced bone defect, which provide a promising application of rFSAV for the treatment of bone infection for orthopedic applications.

D-mannose acts as a V-ATPase inhibitor to suppress inflammatory cytokines generation and bacterial killing in macrophage

Vacuolar-type H+-ATPase (V-ATPase) critically controls phagosome acidification to promote pathogen digestion and clearance in macrophage. However, the specific subunits of V-ATPase have been evidenced to play contradictory functions in inflammatory cytokines generation and secretion exposure to external bacterial or LPS stimulation. Therefore, identifying the unique function of the separate subunit of V-ATPase is extremely important to regulate macrophage function. Here, we found that D-mannose, a C-2 epimer of glucose, suppressed ATP6V1B2 lysosomal translocation to inhibit V-ATPase activity in macrophages, thereby causing the scaffold protein axis inhibitor protein (AXIN) recruitment to lysosomal membrane and AMPK activation. Correspondingly, LPS-stimulated macrophage M1 polarization was significantly suppressed by D-mannose via down-regulating NF-κB signaling pathway in response to AMPK activation, while IL-4 induced macrophage M2 polarization were not affected. Furthermore, the failure of lysosomal localization of ATP6V1B2 caused by D-mannose also led to the acidification defects of lysosome. Therefore, D-mannose displayed a remarkable function in inhibiting macrophage phagocytosis and bacterial killing. Taken together, D-mannose acts a novel V-ATPase suppressor to attenuate macrophage inflammatory production but simultaneously prevent macrophage phagocytosis and bacterial killing.

An injectable bioactive dressing based on platelet-rich plasma and nanoclay: Sustained release of deferoxamine to accelerate chronic wound healing

Delayed diabetic wound healing has placed an enormous burden on society. The key factors limiting wound healing include unresolved inflammation and impaired angiogenesis. Platelet-rich plasma (PRP) gel, a popular biomaterial in the field of regeneration, has limited applications due to its non-injectable properties and rapid release and degradation of growth factors. Here, we prepared an injectable hydrogel (DPLG) based on PRP and laponite by a simple one-step mixing method. Taking advantages of the non-covalent interactions, DPLG could overcome the limitations of PRP gels, which is injectable to fill irregular injures and could serve as a local drug reservoir to achieve the sustained release of growth factors in PRP and deferoxamine (an angiogenesis promoter). DPLG has an excellent ability in accelerating wound healing by promoting macrophage polarization and angiogenesis in a full-thickness skin defect model in type I diabetic rats and normal rats. Taken together, this study may provide the ingenious and simple bioactive wound dressing with a superior ability to promote wound healing.

Induction of a different immune response in non-titanized compared to titanized polypropylene meshes

It is well known that pelvic organ prolapse (POP) significantly reduces the quality of life of affected women and in many cases requires corrective surgery. Aim of the study was to compare the immune response against titanized versus non-titanized meshes, especially macrophage polarization and immune checkpoint association. For this, we analyzed 644 POP surgeries, which were performed between 2017 and 2022, in our department. Four of them needed revision surgery caused by erosion. We analyzed the influx of CD68 & CD163 positive macrophages and the expression of immune checkpoint molecules PD-L1 and PD1 in these 4 patients. We identified a large number of CD68 and CD163 positive macrophages and additionally a PD-L1 expression of these cells. Based on the in-vivo results, we isolated monocytes and co-cultivated monocytes with different mesh material covered with or without fibroblasts. We identified a significantly enhanced macrophage activation and PD-L1 expression in macrophages surrounding non-titanized polypropylene mesh material. Encapsulation of the material by fibroblasts was crucial for that. Specifically, CD68-positive macrophages are upregulated (p < 0.001), co-expressing PD-L1 (p < 0.001) in monocytes co-cultivated with non-titanized polypropylene meshes. Monocytes co-cultivated with titanized polypropylene meshes showed significantly lower expression of CD163 (p = 0.027) and PD-L1 (p = 0.022). In conclusion, our in vitro data suggest that the titanium coating leads to a decreased polarization of macrophages and to a decreased immune response compared to non-titanized meshes. This could be an indication for the increased incidence of erosion of the non-titanized meshes, which is a severe complication of this procedure and requires revision surgery. STATEMENT OF SIGNIFICANCE: Pelvic organ prolapse is a well-known problem for women and often requires corrective surgery. Polypropylene meshes are often used, which differ in their coating (titanized vs. non-titanized). A severe side effect of these surgeries is mesh erosion, due to onset of inflammation, which requires revision surgery. We examined all erosion cases (4 of 644 patients) with implanted nontitanium-coated meshes by immunohistochemistry and found upregulation of macrophage polarization (as markers CD68 and CD163) and increased expression of the immune checkpoint molecules PD-L1 and PD1. This suggests inflammatory processes and an enhanced immune response. In addition, we set up an in vitro experiment to investigate whether coating plays a role. Here, we demonstrated that the non-titanized meshes elicited a significantly higher immune response in comparison to titanized meshes, which could lead to the higher erosion rate of the non-titanized meshes. Our results highlight the benefit of titanized meshes, which should lead to a lower revision surgery rate and thus improved patient outcome.

Tailoring the multiscale mechanics of tunable decellularized extracellular matrix (dECM) for wound healing through immunomodulation

With the discovery of the pivotal role of macrophages in tissue regeneration through shaping the tissue immune microenvironment, various immunomodulatory strategies have been proposed to modify traditional biomaterials. Decellularized extracellular matrix (dECM) has been extensively used in the clinical treatment of tissue injury due to its favorable biocompatibility and similarity to the native tissue environment. However, most reported decellularization protocols may cause damage to the native structure of dECM, which undermines its inherent advantages and potential clinical applications. Here, we introduce a mechanically tunable dECM prepared by optimizing the freeze-thaw cycles. We demonstrated that the alteration in micromechanical properties of dECM resulting from the cyclic freeze-thaw process contributes to distinct macrophage-mediated host immune responses to the materials, which are recently recognized to play a pivotal role in determining the outcome of tissue regeneration. Our sequencing data further revealed that the immunomodulatory effect of dECM was induced via the mechnotrasduction pathways in macrophages. Next, we tested the dECM in a rat skin injury model and found an enhanced micromechanical property of dECM achieved with three freeze-thaw cycles significantly promoted the M2 polarization of macrophages, leading to superior wound healing. These findings suggest that the immunomodulatory property of dECM can be efficiently manipulated by tailoring its inherent micromechanical properties during the decellularization process. Therefore, our mechanics-immunomodulation-based strategy provides new insights into the development of advanced biomaterials for wound healing.

LncRNA MIR4435-2HG suppression regulates macrophage M1/M2 polarization and reduces intestinal inflammation in mice with ulcerative colitis

OBJECTIVE

To explore the effect and potential mechanism of LncRNA MIR4435-2HG on macrophage polarization and intestinal inflammation in ulcerative colitis (UC). Methods RAW264.7 macrophage cells stimulated with lipopolysaccharide (LPS) were co-cultured with Caco-2 cells to establish an inflammatory model of UC in vitro. Balb/c mice were orally administered dextran sulfate sodium (DSS) to establish an in vivo UC model. Flow cytometry and immunohistochemical (IHC) analyses were performed to assess the levels of surface phenotype markers. RT-qPCR and enzyme-linked immunosorbent assay (ELISA) were performed to measure the levels of inflammatory cytokines. Western blotting was used to analyze expression of the tight junction protein zona occludens 1 (ZO-1) and the key proteins of the JAK1/STAT1 signaling pathway (Janus kinase-1(JAK1), p-JAK1, signal transducer and activator of transcription 1 (STAT1), p-STAT1. Results In in vitro experiments, we found that inhibition of MIR4435-2HG was able to decrease the levels of CD68, iNOS, IL-6, and TEER, and increase the levels of CD206, Arg-1, IGF-1, and ZO-1. Meanwhile, inhibition of MIR4435-2HG significantly suppressed the levels of p- JAK1 and p- STAT1. In addition, we further demonstrated by in vivo experiments that inhibition of MIR4435-2HG significantly attenuated intestinal inflammation in mice, as evidenced by increased body weight, increased colon length and weight, decreased fecal scores, hemorrhagic scores, and DAI scores, and amelioration of colonic injury, and decreased inflammatory factors. Conclusions MIR4435-2HG suppression inhibits macrophage M1 polarization while promoting M2 polarization, thereby alleviating intestinal inflammation in mice with ulcerative colitis through JAK1/STAT1 signaling.

Carbon monoxide (CO) derived from the CO-releasing molecule CORM-2 reduces peritoneal adhesion formation in a rat model

BACKGROUND

Although low-dose carbon monoxide (CO) administration has been shown to have an anti-fibrotic effect in various fibrotic diseases, its effects on peritoneal adhesion (PA), one of the postoperative complications, are not elucidated. In this study, the effect of CO-releasing tricarbonyldichlororuthenium (II) dimer (CORM-2) administration on the formation of PA and the underlying factors of its potential effect were investigated.

METHODS AND RESULTS

After the induction of PA, rats were divided into four groups with 8 rats in each group. The rats received either (i) dimethyl sulfoxide:saline solution (1:10) as a vehicle, (ii) 2.5 mg/kg CORM-2, (iii) 5 mg/kg CORM-2, or (iv) inactive (i) CORM (iCORM) intragastrically every day for a duration of 7 days. PA was not induced in rats (n = 8) designated as sham controls. Gross, histological, immunohistochemical and quantitative real-time polymerase chain reaction analyses were performed to evaluate the effectiveness of CORM-2 administration. Gross analysis showed that CORM-2 administration reduced PA formation compared to rats treated with vehicle. Histological and immunohistochemical examinations showed that increased collagen deposition, myofibroblast accumulation, microvessel density, and M1 macrophage count in the peritoneal fibrosis area of vehicle-treated rats decreased following CORM-2 treatments. PCR analyses showed that CORM-2 treatments decreased hypoxia-induced Hif1a, profibrotic Tgfb1, ECM components Col1a1 and Col3a1, collagen degradation suppressor Timp1, fibrinolysis inhibitor Serpine1, and pro-inflammatory Tnf mRNA expressions, while increasing the M2 macrophage marker Arg1 mRNA expression.

CONCLUSIONS

These results suggested that CORM-2 administration reduces PA formation by affecting adhesiogenic processes such as pro-inflammatory response, fibrinolytic system, angiogenesis and fibrogenesis.

The effect of m2 peptide targeted nanoliposomes containing crocin on induction of phenotypic change in tumor macrophages to M1 state

AIMS

Crocin has immunomodulatory and anticancer effects. In this study, crocin was used to induce the M1 phenotype in mouse tumor macrophages.

MAIN METHODS

A targeted liposomal formulation with m2 peptide was prepared and characterized to deliver crocin to the M2 macrophages present in the tumor environment. RT-qPCR and IHC were performed for in vitro and in vivo (in C26 colon carcinoma mouse model at a dose of 50 mg/kg) assessment of M1 induction, respectively.

KEY FINDINGS

In vitro results indicated that liposome modified with m2 peptide was non-toxic to macrophages and had an improved uptake by macrophages compared to the non-targeted formulation and induced M1 phenotype through an IL6-independent pathway. M2 peptide- modified liposome showed considerable tumor accumulation and anti-tumor effects and significantly shifted the phenotype of tumor macrophages towards an anti-tumor M1 phenotype.

SIGNIFICANCE

Probably the remarkable anti-tumor responses observed in this study with m2 peptide-targeted liposomal formulations containing crocin were due to the enhanced delivery of crocin to the tumor macrophage and the subsequent initiation of anti-tumor immune responses.

Hsa_circRNA_103124 upregulation in Crohn's disease promoted macrophage M1 polarization to maintain an inflammatory microenvironment via activation of the AKT2 and TLR4/NF-κB pathways

An accumulating body of research indicates that circular RNAs participate in the pathogenesis of Crohn's disease (CD). Hsa_circRNA_103124, which was upregulated in the peripheral blood mononuclear cells of patients with CD, was reported to inhibit autophagy in our previous studies. However, how hsa_circRNA_103124 participates in CD progression remains unclear. In this study, TLR4 was found to be upregulated in THP1 cells overexpressing hsa_circRNA_103124. Bioinformatic analysis indicated that overexpressed hsa_circRNA_103124 was associated with the PI3K/AKT signaling pathway and TLR4-associated innate immunity in inflammatory bowel disease. Therefore, we inferred a possible role for hsa_circRNA_103124 in macrophage polarization. Hsa_circRNA_103124, AKT2 and TLR4 were significantly upregulated in the PBMCs of patients with CD. Further analysis revealed a positive correlation between hsa_circRNA_103124 and AKT2 (r = 0.8029, p < 0.0001), TLR4 (r = 0.2529, p = 0.0089) and the Crohn's disease activity index (r = 0.4535, p < 0.0001) in patients with CD. Notably, hsa_circRNA_103124 promoted macrophage M1 polarization with increased expression of CD80 and CD86, while it inhibited macrophage M2 polarization with decreased expression of CD206 and CD163. Hsa_circRNA_103124 promoted an inflammatory microenvironment by activating the AKT2 and TLR4/NF-κB signaling pathways in M1 polarized THP1 cells. Nevertheless, hsa-miR-650 reversed the role of hsa_circRNA_103124 in M1 polarization. Hsa_circRNA_103124 promoted the formation of neutrophil extracellular traps and reduced the expression of ZO-1. In summary, the results of this study indicated that hsa_circRNA_103124 promoted macrophage M1 polarization to maintain an inflammatory microenvironment via activation of the TLR4/NF-κB pathway in a hsa-miR-650/AKT2 dependent manner. Hsa_circRNA_103124 could serve as a potential biomarker and a novel therapeutic target in CD progression.

Overexpression of Pasteurella multocida OmpA induces transcriptional changes and its possible implications for the macrophage polarization

Pasteurella multocida (P. multocida) is a highly infectious, zoonotic pathogen. Outer membrane protein A (OmpA) is an important virulence component of the outer membrane of P. multocida. OmpA mediates bacterial biofilm formation, eukaryotic cell infection, and immunomodulation. It is unclear how OmpA affects the host immune response. We estimated the role of OmpA in the pathogenesis of P. multocida by investigating the effect of OmpA on the immune cell transcriptome. Changes in the transcriptome of rat alveolar macrophages (NR8383) upon overexpression of P. multocida OmpA were demonstrated. A model cell line for stable transcription of OmpA was constructed by infecting NR8383 cells with OmpA-expressing lentivirus. RNA was extracted from cells and sequenced on an Illumina HiSeq platform. Key gene analysis of genes in the RNA-seq dataset were performed using various bioinformatics methods, such as gene ontology enrichment analysis, Kyoto Encyclopedia of Genes and Genomes enrichment analysis, Gene Set Enrichment Analysis, and Protein-Protein Interaction Analysis. Our findings revealed 1340 differentially expressed genes. Immune-related pathways that were significantly altered in rat alveolar macrophages under the effect of OmpA included focal adhesion, extracellular matrix and vascular endothelial growth factor signaling pathways, antigen processing and presentation, nucleotide oligomerization domain-like receptor and Toll-like receptor signaling pathways, and cytokine-cytokine receptor interaction. The key genes screened were Vegfa, Igf2r, Fabp5, P2rx1, C5ar1, Nedd4l, Gas6, Cxcl1, Pf4, Pdgfb, Thbs1, Col7a1, Vwf, Ccl9, and Arg1. Data of associated pathways and altered gene expression indicated that OmpA might cause the conversion of rat alveolar macrophages to M2-like. The related pathways and key genes can serve as a reference for OmpA of P. multitocida and host interaction mechanism studies.

Substance P promote macrophage M2 polarization to attenuate secondary lymphedema by regulating NF-kB/NLRP3 signaling pathway

Secondary lymphedema often occurs after filariasis, trauma, lymph node dissection and radiation therapy, which is manifested by infiltration of inflammatory cells and fibrosis formation in pathologically. Substance P is a widely used neuropeptide in the field of tissue repair, while the regenerative potential of the substance P has not been proven in the secondary lymphedema. In this study, animal model of secondary lymphedema was constructed by excising the skin and subcutaneous lymphatic network in the tail of mice, and the degree of swelling in the tail of mice was evaluated after 6 weeks under the treatment with substance P. Immunofluorescence staining was also performed to assess immune cell infiltration, subcutaneous fibrosis and lymphangiogenesis. The results revealed that substance P significantly alleviated post-surgical lymphedema in mice. Furthermore, we found that substance P promoted macrophages M2 polarization, a process associated with downregulation of the NF-kB/NLRP3 pathway. After application of disodium clodronate (macrophage scavenger, CLO), the positive effect of substance P in lymphedema is significantly inhibited. In vitro experiments, we further demonstrated the polarizing effect of substance P on bone marrow-derived macrophages (BMDMs), while substance P inhibited the activation of the NF-kB/NLRP3 pathway in BMDMs after the treatment of lipopolysaccharide (LPS). In addition, polarized macrophages were demonstrated to promote the proliferation, tube-forming and migratory functions of human lymphatic endothelial cells (hLEC). In conclusion, our study provides preliminary evidence that substance P alleviates secondary lymphedema by promoting macrophage M2 polarization, and this therapeutic effect may be associated with downregulation of the NF-kB/NLRP3 pathway.

OTUB1's role in promoting OSCC development by stabilizing RACK1 involves cell proliferation, migration, invasion, and tumor-associated macrophage M1 polarization

Ovarian tumor domain, ubiquitin aldehyde binding 1 (OTUB1), a deubiquitinating enzyme known to regulate the stability of downstream proteins, has been reported to regulate various cancers tumorigenesis, yet its direct effects on oral squamous cell carcinoma (OSCC) progression are unclear. Bioinformatics analysis was performed to screen for genes of interest, and in vitro and in vivo studies were carried out to investigate the function and mechanism of OTUB1 in OSCC. We found that OTUB1 was abnormally elevated in OSCC tissues and positively associated with the pathological stage and tumor stage. Knockdown of OTUB1 impaired the malignance of OSCC cells - suppressed cell proliferation, invasion, migration, and xenografted tumor growth. OTUB1 silencing also drove tumor-associated macrophage M1 polarization but suppressed M2 polarization, and the induction of M1 polarization inhibited the survival of OSCC cells. However, OTUB1 overexpression exerted the opposite effects. Furthermore, the protein network that interacted with the OTUB1 protein was constructed based on the GeneMANIA website. Receptor for activated C kinase 1 (RACK1), a facilitator of OSCC progression, was identified as a potential target of the OTUB1 protein. We revealed that OTUB1 positively regulated RACK1 expression and inhibited RACK1 ubiquitination. Additionally, RACK1 upregulation reversed the effects of OTUB1 knockdown on OSCC progression. Overall, we demonstrated that OTUB1 might regulate OSCC progression by maintaining the stability of the RACK1 protein. These findings highlight the potential roles of the OTUB1/RACK1 axis as a potential therapeutic target in OSCC.

Autophagy suppression facilitates macrophage M2 polarization via increased instability of NF-κB pathway in hepatocellular carcinoma

The tumor microenvironment is a highly heterogeneous circumstance composed of multiple components, while tumor-associated macrophages (TAMs) are major innate immune cells with highly plastic and are always educated by tumor cells to structure an advantageous pro-tumor immune microenvironment. Despite emerging evidence focalizing the role of autophagy in other immune cells, the regulatory mechanism of autophagy in macrophage polarization remains poorly understood. Herein, we demonstrated that hepatocellular carcinoma (HCC) cells educated macrophages toward M2-like phenotype polarization under the condition of coculture. Moreover, we observed that inhibition of macrophage autophagy promoted M2-like macrophage polarization, while the tendency was impeded when autophagy was motivated. Mechanistically, macrophage autophagy inhibition inactivates the NF-κB pathway by increasing the instability of TAB3 via ubiquitination degradation, which leads to the M2-like phenotype polarization of macrophages. Both immunohistochemistry staining using human HCC tissues and experiment in vivo verified autophagy inhibition is correlated with M2 macrophage polarization. Altogether, we illustrated that macrophage autophagy was involved in the process of HCC cells domesticating M2 macrophage polarization via the NF-κB pathway. These results provide a new target to interfere with the polarization of macrophages to M2-like phenotype during HCC progression.

Atmosphere-inspired multilayered nanoarmor with modulable protection and delivery of Interleukin-4 for inflammatory microenvironment modulation

Inflammatory bowel disease (IBD) has been closely associated with immune disorders and excessive M1 macrophage activation, which can be reversed by the M2-polarizing effect of interleukin-4 (IL-4). However, maintaining native IL-4 activity with its specific release in the inflammatory microenvironment and efficient biological performance remain a challenge. Inspired by the multilayered defense mechanism of the earth's atmosphere, we constructed a multilayered protective nanoarmor (NA) for IL-4 delivery (termed as IL-4@PEGRA NAs) into an intricate inflammatory microenvironment. The poly(ethylene glycol) (PEG)-ylated phenolic rosmarinic acid (RA)-grafted copolymer contains two protective layers-the intermediate polyphenol (RA molecules) and outermost shield (PEG) layers-to protect the biological activity of IL-4 and prolong its circulation in blood. Moreover, IL-4@PEGRA NAs scavenge reactive oxygen species with the specific release of IL-4 and maximize its biofunction at the site of inflammation, leading to M2 macrophage polarization and downregulation of inflammatory mediators. Simultaneously, gut microbiota dysbiosis can improve to amplify the M2-polarizing effect and inhibit the phosphatidylinositol 3 kinase/Akt signaling pathway, thereby attenuating inflammation and promoting colitis tissue repair. It provides a nature-inspired strategy for constructing an advanced multilayered NA delivery system with protective characteristics and potential for IBD management.

Mesenchymal stem cell-derived extracellular vesicles prevent the formation of pulmonary arterial hypertension through a microRNA-200b-dependent mechanism

BACKGROUND

Bone marrow mesenchymal stem cell-derived extracellular vesicles (BMSC-EVs) have been highly studied with their critical roles as carriers of therapeutic targets such as microRNAs (miRNAs) in the treatment of human diseases, including pulmonary arterial hypertension (PAH). Herein, we tried to study the potential of BMSC-EVs to deliver miR-200b for the regulation of macrophage polarization in PAH.

METHODS

Rat models of PAH were induced with monocrotaline treatment, followed by miR-200b expression detection in lung tissues, pulmonary artery smooth muscle cells (PASMCs) and macrophages. miR-200b-containing BMSCs or miR-200b-deficient BMSCs were selected to extract EVs. Then, we assessed the changes in rats with PAH-associated disorders as well as in vitro macrophage polarization and the functions of PASMCs after treatment with BMSC-EVs. Moreover, the interaction between miR-200b, phosphodiesterase 1 A (PDE1A) was identified with a luciferase assay, followed by an exploration of the downstream pathway, cAMP-dependent protein kinase (PKA).

RESULTS

miR-200b was reduced in lung tissues, PASMCs and macrophages of rats with PAH-like pathology. BMSC-EVs transferred miR-200b into macrophages, and subsequently accelerated their switch to the M2 phenotype and reversed the PAH-associated disorders. Furthermore, miR-200b carried by BMSC-EVs induced PKA phosphorylation by targeting PDE1A, thereby expediting macrophage polarization.

CONCLUSION

Our current study highlighted the inhibitory role of BMSC-EV-miR-200b in PAH formation.

Exosomes derived from LPS-preconditioned bone marrow-derived MSC modulate macrophage plasticity to promote allograft survival via the NF-κB/NLRP3 signaling pathway

OBJECTIVES

This study investigated whether exosomes from LPS pretreated bone marrow mesenchymal stem cells (LPS pre-MSCs) could prolong skin graft survival.

METHODS

The exosomes were isolated from the supernatant of MSCs pretreated with LPS. LPS pre-Exo and rapamycin were injected via the tail vein into C57BL/6 mice allografted with BALB/c skin; graft survival was observed and evaluated. The accumulation and polarization of macrophages were examined by immunohistochemistry. The differentiation of macrophages in the spleen was analyzed by flow cytometry. For in vitro, an inflammatory model was established. Specifically, bone marrow-derived macrophages (BMDMs) were isolated and cultured with LPS (100 ng/ml) for 3 h, and were further treated with LPS pre-Exo for 24 h or 48 h. The molecular signaling pathway responsible for modulating inflammation was examined by Western blotting. The expressions of downstream inflammatory cytokines were determined by Elisa, and the polarization of macrophages was analyzed by flow cytometry.

RESULTS

LPS pre-Exo could better ablate inflammation compared to untreated MSC-derived exosomes (BM-Exo). These loaded factors inhibited the expressions of inflammatory factors via a negative feedback mechanism. In vivo, LPS pre-Exo significantly attenuated inflammatory infiltration, thus improving the survival of allogeneic skin graft. Flow cytometric analysis of BMDMs showed that LPS pre-Exo were involved in the regulation of macrophage polarization and immune homeostasis during inflammation. Further investigation revealed that the NF-κB/NLRP3/procaspase-1/IL-1β signaling pathway played a key role in LPS pre-Exo-mediated regulation of macrophage polarization. Inhibiting NF-κB in BMDMs could abolish the LPS-induced activation of inflammatory pathways and the polarization of M1 macrophages while increasing the proportion of M2 cells.

CONCLUSION

LPS pre-Exo are able to switch the polarization of macrophages and enhance the resolution of inflammation. This type of exosomes provides an improved immunotherapeutic potential in prolonging graft survival.

Loss of LEAP-2 alleviates obesity-induced myocardial injury by regulating macrophage polarization

BACKGROUND

Obesity is a serious public health issue worldwide, which is a risk factor of cardiovascular disorders. Obesity has been shown to be associated with subclinical myocardial injury, increasing the risk of heart failure. Our study aims to explore novel mechanisms underlying obesity-induced myocardial injury.

METHODS

Mice were fed a high-fat diet (HFD) to establish a mouse model of obesity, and serum levels of TG, TCH, LDL, CK-MB, LDH, cTnI and BNP were examined. Inflammatory response was evaluated by determining the expression and secretion of proinflammatory cytokines IL-1β and TNF-α. Macrophage infiltration in the heart was examined by IHC staining, and H&E staining was applied to evaluate myocardial injury. Primary peritoneal macrophages were isolated from mice and treated with palmitic acid (PA). Macrophage polarization was evaluated by determine the expression of CCL2, iNOS, CD206 and arginase I via Western blot, RT-qPCR, and flow cytometry. Co-IP assays were performed to examine the interaction between LEAP-2, GHSR and ghrelin.

RESULTS

Hyperlipidemia, increased proinflammatory cytokines and myocardial injury were observed in mice with obesity, and silencing of LEAP-2 ameliorated HFD-induced hyperlipidemia, inflammation, and myocardial injury. Moreover, HFD-induced macrophage infiltration and M1 polarization were reversed by LEAP-2 knockdown in mice. Furthermore, silencing of LEAP-2 suppressed PA-induced M1 polarization but enhanced M2 polarization in vitro. LEAP-2 interacted with GHSR in macrophages, and knockdown of LEAP-2 promoted the interaction of GHSR and ghrelin. Overexpression of ghrelin enhanced LEAP-1 silencing-mediated suppression of inflammatory response and upregulation of M2 polarization in PA-induced macrophages.

CONCLUSION

Knockdown of LEAP-2 ameliorates obesity-induced myocardial injury via promoting M2 polarization.

STING signaling activation modulates macrophage polarization via CCL2 in radiation-induced lung injury

BACKGROUND

Radiation-induced lung injury (RILI) is a prevalent complication of thoracic radiotherapy in cancer patients. A comprehensive understanding of the underlying mechanisms of RILI is essential for the development of effective prevention and treatment strategies.

METHODS

To investigate RILI, we utilized a mouse model that received 12.5 Gy whole-thoracic irradiation. The evaluation of RILI was performed using a combination of quantitative real-time polymerase chain reaction (qRT-PCR), enzyme-linked immunosorbent assay (ELISA), histology, western blot, immunohistochemistry, RNA sequencing, and flow cytometry. Additionally, we established a co-culture system consisting of macrophages, lung epithelial cells, and fibroblasts for in vitro studies. In this system, lung epithelial cells were irradiated with a dose of 4 Gy, and we employed STING knockout macrophages. Translational examinations were conducted to explore the relationship between STING expression in pre-radiotherapy lung tissues, dynamic changes in circulating CCL2, and the development of RILI.

RESULTS

Our findings revealed significant activation of the cGAS-STING pathway and M1 polarization of macrophages in the lungs of irradiated mice. In vitro studies demonstrated that the deficiency of cGAS-STING signaling led to impaired macrophage polarization and RILI. Through RNA sequencing, cytokine profiling, and rescue experiments using a CCL2 inhibitor called Bindarit, we identified the involvement of CCL2 in the regulation of macrophage polarization and the development of RILI. Moreover, translational investigations using patient samples collected before and after thoracic radiotherapy provided additional evidence supporting the association between cGAS-STING signaling activity, CCL2 upregulation, and the development of radiation pneumonitis.

CONCLUSIONS

The cGAS-STING signaling pathway plays a crucial role in regulating the recruitment and polarization of macrophages, partly through CCL2, during the pathogenesis of RILI.

The Role of Immune Mechanisms in Abdominal Aortic Aneurysm: Could It be a Promising Therapeutic Strategy?

Abdominal aortic aneurysm (AAA) is an enlargement of the aorta greater than 50% in diameter. Although up to 80% of cases result in mortality if the aneurysm ruptures, patients are often diagnosed too late, as most cases are asymptomatic. The current treatment for AAA is still surgery as there are currently no effective drug treatments. Knowledge of the pathophysiological mechanisms is essential for the development of new preventive and therapeutic approaches. However, the molecular mechanisms are complex and remain unclear. Apoptosis of vascular smooth muscle cells, the major cellular component of the aorta, and degeneration of the extracellular matrix, the skeleton of the aortic wall, are hallmarks of AAA pathology. Inflammation, mainly through macrophage cells, has been recognized as a central factor in the development of AAA. Macrophage cells also orchestrate other pathways and immune cells involved in this process. Macrophages do not exist as pure populations at aneurysm sites. M1 macrophages are pro-inflammatory and weaken the aortic wall during AAA development. M2 macrophages, in contrast, are involved in anti-inflammatory reactions and aorta tissue repair. The balancing effect on AAA progression makes M1/M2 macrophages therapeutic targets to control inflammation and destruction of the aortic wall. An early diagnosis is also important to allow for early interventions. This review article, based on the available data, aims to evaluate the role of an immunotherapeutic approach in controlling AAA development by briefly discussing the immunological mechanisms.

Tumor-derived CircRNA_102191 promotes gastric cancer and facilitates M2 macrophage polarization

BACKGROUND

Gastric cancer is a common malignant tumor of the digestive tract and the fourth leading cause of death from cancer-related diseases. In recent years, many studies have found that circular RNAs play an important role in cancer. Tumor-associated macrophages (TAMs) are also critical for tumor progression.

OBJECTIVE

This study examined the role of circRNA_102191 in gastric cancer progression.

METHODS

The relative mRNA levels were determined by qRT-PCR. Western blotting and ELISA were used to detect the protein levels. In vitro proliferation was assessed using CCK8 and clonogenic assays. The migration and invasion of cell lines were assessed by transwell-based assays. The interactions between molecules were detected using a luciferase reporter assay. M0 macrophages were induced with PMA. M1 macrophages were induced with LPS and IFN-γ, and M2 macrophages were induced with IL-4.

RESULTS

The expression of circRNA_102191 was enhanced significantly in gastric cancer cell lines and clinical tumor tissues. CircRNA_102191 promotes gastric cancer cell progression by regulating miR-493-3p and its downstream target gene XPR1. CircRNA_102191 can enhance the EMT process of gastric cancer cells by promoting the M2 polarization of macrophages.

CONCLUSION

CircRNA_102191 promotes the biological function of gastric cancer cells by regulating the miR-493-3p/XPR1 axis and M2 macrophage polarization.

Tumor cell-derived exosomes regulate macrophage polarization: Emerging directions in the study of tumor genesis and development

As an extracellular vesicle, exosomes play an important role in intercellular information transmission, delivering cargos of the parent cell, such as RNA, DNA, proteins, and lipids, activating different signaling pathways in the target cell and regulating inflammation, angiogenesis, and tumor progression. In particular, exosomes secreted by tumor cells can change the function of surrounding cells, creating a microenvironment conducive to tumor growth and metastasis. For example, after macrophages phagocytose exosomes and accept their cargos, they activate macrophage polarization-related signaling pathways and polarize macrophages into M1 or M2 types to exert antitumor or protumor functions. Currently, the study of exosomes affecting the polarization of macrophages has attracted increasing attention. Therefore, this paper reviews relevant studies in this field to better understand the mechanism of exosome-induced macrophage polarization and provide evidence for exploring novel targets for tumor therapy and new diagnostic markers in the future.

Gut microbiota-derived short-chain fatty acids promote prostate cancer progression via inducing cancer cell autophagy and M2 macrophage polarization

We have previously demonstrated abnormal gut microbial composition in castration-resistant prostate cancer (CRPC) patients, here we revealed the mechanism of gut microbiota-derived short-chain fatty acids (SCFAs) as a mediator linking CRPC microbiota dysbiosis and prostate cancer (PCa) progression. By using transgenic TRAMP mouse model, PCa patient samples, in vitro PCa cell transwell and macrophage recruitment assays, we examined the effects of CRPC fecal microbiota transplantation (FMT) and SCFAs on PCa progression. Our results showed that FMT with CRPC patients' fecal suspension increased SCFAs-producing gut microbiotas such as Ruminococcus, Alistipes, Phascolarctobaterium in TRAMP mice, and correspondingly raised their gut SCFAs (acetate and butyrate) levels. CRPC FMT or SCFAs supplementation significantly accelerated mice's PCa progression. In vitro, SCFAs enhanced PCa cells migration and invasion by inducing TLR3-triggered autophagy that further activated NF-κB and MAPK signalings. Meanwhile, autophagy of PCa cells released higher level of chemokine CCL20 that could reprogramme the tumor microenvironment by recruiting more macrophage infiltration and simultaneously polarizing them into M2 type, which in turn further strengthened PCa cells invasiveness. Finally in a cohort of 362 PCa patients, we demonstrated that CCL20 expression in prostate tissue was positively correlated with Gleason grade, pre-operative PSA, neural/seminal vesical invasion, and was negatively correlated with post-operative biochemical recurrence-free survival. Collectively, CRPC gut microbiota-derived SCFAs promoted PCa progression via inducing cancer cell autophagy and M2 macrophage polarization. CCL20 could become a biomarker for prediction of prognosis in PCa patients. Intervention of SCFAs-producing microbiotas may be a useful strategy in manipulation of CRPC.

Blockade of C5aR1 alleviates liver inflammation and fibrosis in a mouse model of NASH by regulating TLR4 signaling and macrophage polarization

BACKGROUND

Nonalcoholic steatohepatitis (NASH) is an advanced form of chronic fatty liver disease, which is a driver of hepatocellular carcinoma. However, the roles of the C5aR1 in the NASH remain poorly understood. Here, we aimed to investigate the functions and mechanisms of the C5aR1 on hepatic inflammation and fibrosis in murine NASH model.

METHODS

Mice were fed a normal chow diet with corn oil (ND + Oil), a Western diet with corn oil (WD + Oil) or a Western diet with carbon tetrachloride (WD + CCl4) for 12 weeks. The effects of the C5a-C5aR1 axis on the progression of NASH were analyzed and the underlying mechanisms were explored.

RESULTS

Complement factor C5a was elevated in NASH mice. C5 deficiency reduced hepatic lipid droplet accumulation in the NASH mice. The hepatic expression levels of TNFα, IL-1β and F4/80 were decreased in C5-deficient mice. C5 loss alleviated hepatic fibrosis and downregulated the expression levels of α-SMA and TGFβ1. C5aR1 deletion reduced inflammation and fibrosis in NASH mice. Transcriptional profiling of liver tissues and KEGG pathway analysis revealed that several pathways such as Toll-like receptor signaling, NFκB signaling, TNF signaling, and NOD-like receptor signaling pathway were enriched between C5aR1 deficiency and wild-type mice. Mechanistically, C5aR1 deletion decreased the expression of TLR4 and NLRP3, subsequently regulating macrophage polarization. Moreover, C5aR1 antagonist PMX-53 treatment mitigated the progression of NASH in mice.

CONCLUSIONS

Blockade of the C5a-C5aR1 axis reduces hepatic steatosis, inflammation, and fibrosis in NASH mice. Our data suggest that C5aR1 may be a potential target for drug development and therapeutic intervention of NASH.

Paeonol accelerates skin wound healing by regulating macrophage polarization and inflammation in diabetic rats

Diabetic ulcer is usually seen in people with uncontrolled blood sugar. Reportedly, many factors such as impaired glucose metabolism, and macrovascular and microvascular diseases caused angiogenesis disorders and delayed the healing of diabetic ulcers, thus affecting the body's metabolism, nutrition, and immune function. This study aimed to explore the effect of paeonol on skin wound healing in diabetic rats and the related mechanism. A rat model of diabetic ulcer was established. High glucose-treated mouse skin fibroblasts were co-cultured with M1 or M2-polarized macrophages treated with or without paeonol. H&E and Masson staining were used to reveal inflammatory cell infiltration and collagen deposition, respectively. Immunohistochemistry visualized the expression of Ki67, CD31, and vascular endothelial growth factor (VEGF). Western blot was used to detect interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-4, IL-10, CD31, VEGFA, and collagen I/III. The expression of iNOS and arginase 1 was revealed by immunofluorescence staining. Paeonol treatment augmented collagen deposition and the expression of Ki67, CD31, VEGF, and macrophage M2 polarization markers (IL-4 and IL-10) and reduced wound area, inflammatory cell infiltration, and macrophage M1 polarization markers (IL-1β and TNF-α) in the ulcerated area. In vitro, paeonol treatment promoted M2-polarization and repressed M1-polarization in macrophages, thereby improving the repair of cell damage induced by high glucose. Paeonol accelerates the healing of diabetic ulcers by promoting M2 macrophage polarization and inhibiting M1 macrophage polarization.

P2Y11/IL-1 receptor crosstalk controls macrophage inflammation: a novel target for anti-inflammatory strategies?

Although first cloning of the human ATP receptor P2Y11 was successful 25 years ago, the exact downstream signaling pathways of P2Y11 receptor, which can couple to Gq and Gs proteins, have remained unclear. Especially the lack of rodent models as well as the limited availability of antibodies and pharmacological tools have hampered examination of P2Y11 expression and function. Many meaningful observations related to P2Y11 have been made in primary immune cells, indicating that P2Y11 receptors are important regulators of inflammation and cell migration, also by controlling mitochondrial activity. Our recent studies have shown that P2Y11 is upregulated during macrophage development and activates signaling through IL-1 receptor, which is well known for its ability to direct inflammatory and migratory processes. This review summarizes the results of the first transcriptomic and secretomic analyses of both, ectopic and native P2Y11 receptors, and discusses how P2Y11 crosstalk with the IL-1 receptor may govern anti-inflammatory and pro-angiogenic processes in human M2 macrophages.

The hepatic GABAergic system promotes liver macrophage M2 polarization and mediates HBV replication in mice

Macrophages display functional phenotypic plasticity. Hepatitis B virus (HBV) infection induces polarizations of liver macrophages either to M1-like pro-inflammatory phenotype or to M2-like anti-inflammatory phenotype. Gamma-aminobutyric acid (GABA) signaling exists in various non-neuronal cells including hepatocytes and some immune cells. Here we report that macrophages express functional GABAergic signaling components and activation of type A GABA receptors (GABAARs) promotes M2-polarization thus advancing HBV replication. Notably, intraperitoneal injection of GABA or the GABAAR agonist muscimol increased HBV replication in HBV-carrier mice that were generated by hydrodynamical injection of adeno-associated virus/HBV1.2 plasmids (pAAV/HBV1.2). The GABA-augmented HBV replication in HBV-carrier mice was significantly reduced by the GABAAR inhibitor picrotoxin although picrotoxin had no significant effect on serum HBsAg levels in control HBV-carrier mice. Depletion of liver macrophages by liposomal clodronate treatment also significantly reduced the GABA-augmented HBV replication. Yet adoptive transfer of liver macrophages isolated from GABA-treated donor HBV-carrier mice into the liposomal clodronate-pretreated recipient HBV-carrier mice restored HBV replication. Moreover, GABA or muscimol treatment increased the expression of "M2" cytokines in macrophages, but had no direct effect on HBV replication in the HepG2.2.15 cells, HBV1.3-transfected Huh7, HepG2, or HepaRG cells, or HBV-infected Huh7-NTCP cells. Taken together, these results suggest that increasing GABA signaling in the liver promotes HBV replication in HBV-carrier mice by suppressing the immunity of liver macrophages, but not by increasing the susceptibility of hepatocytes to HBV infection. Our study shows that a previously unknown GABAergic system in liver macrophage has an essential role in HBV replication.

Discovery of novel aporphine alkaloid derivative as potent TLR2 antagonist reversing macrophage polarization and neutrophil infiltration against acute inflammation

Toll-like receptor 2 (TLR2) mediated macrophages regulate the protective immune response to infectious microorganisms, but the aberrant activation of macrophages often leads to pathological inflammation, including tissue damage. In this study, we identified antagonists of TLR2 by screening 2100 natural products and subsequently identified Taspine, an aporphine alkaloid, as an excellent candidate. Furthermore, analysis of the 10 steps chemical synthesis route and structural optimization yielded the Taspine derivative SMU-Y6, which has higher activity, better solubility, and improved drug-feasible property. Mechanistic studies and seq-RNA analysis revealed that SMU-Y6 inhibited TLR2 over other TLRs, hindered the formation of TLR2/MyD88 complex, and blocked the downstream NF-κB and MAPK signaling pathway, thus suppressing the release of inflammatory cytokines. SMU-Y6 could stabilize TLR2 and bind to TLR2 protein with a Kd of 0.18 μmol/L. Additionally, SMU-Y6 could efficiently reverse the M1 phenotype macrophage polarization, reduce the production of cytokines as well as infiltration of neutrophiles and alleviate the local inflammation in mice with acute paw edema and colitis. Collectively, we reported the first aporphine alkaloid derivative that selectively inhibits TLR2 with high binding affinity and superior drug-feasible property, thus providing an urgently-needed molecular probe and potential drug candidate for inflammatory and autoimmune disease therapy.

BMP-7 modified exosomes derived from synovial mesenchymal stem cells attenuate osteoarthritis by M2 polarization of macrophages

Background

Although the exosomes derived from mesenchymal stem cells (MSCs) display a therapeutic effect on inflammatory diseases, its application on OA has great limitations due to lack of specificity and targeting. The current study aimed to elucidate the potential therapeutic role of bone morphogenetic proteins-7(BMP-7) modified synovial mesenchymal stem cells-derived exosomes (SMSCs-exo) on OA and mechanism.

Methods

For in vitro experiments, LPS-treated macrophages RAW264.7 were treated with SMSCs-exo (exo) or BMP-7 modified SMSCs-exos (BMP-7-exo). The levels of inflammatory factors were assessed by ELISA. Also, the proportion of iNOS and CD206 positive cells were quantified by flow cytometry. Chondrocytes and RAW264.7 were co-culture to evaluate the effects of macrophage polarization on chondrocytes cellular behaviors. This effect on KOA was verified by an experiment in vivo. HE staining and Safranin fast green staining were used to observe the damage of articular cartilage. Immunohistochemistry was used to determine the expression of collagen II and aggrecan in articular cartilage, as well as the expression of iNOS and CD206 in synovial tissues.

Results

Our in vitro results showed that BMP-7-exo treatment promoted LPS-induced proliferation of macrophages and chondrocytes, and showed a better ability to reduce inflammation by promoting macrophages M2 polarization. After co-culture with LPS treated macrophages, the proliferation rate and migration of chondrocytes were significantly decreased, while the apoptosis was significantly increased. The macrophages treated with BMP-7-exo and exo partially reversed these changes. The chondrocytes in BMP-7-exo group had higher proliferation rate and migration, as well as lower apoptosis compared with the exo group. Also, the in vivo results showed BMP-7-exo treatment improved the pathological changes of KOA and promoted synovial macrophages M2 polarization.

Conclusions

Our results demonstrated that BMP-7-exo attenuated KOA inflammation and cartilage injury by synovial macrophages M2 polarization, suggesting that BMP-7-exo carry much therapeutic potential for OA.

CD73 inhibits titanium particle-associated aseptic loosening by alternating activation of macrophages

Aseptic inflammation is a major cause of late failure in total joint arthroplasty, and the primary factor contributing to the development and perpetuation of aseptic inflammation is classical macrophage activation (M1 phenotype polarization) induced by wear particles. CD73 (ecto-5'-nucleotidase) is an immunosuppressive factor that establishes an adenosine-induced anti-inflammatory environment. Although CD73 has been shown to suppress inflammation by promoting alternate macrophage activation (M2 phenotype polarization), its role in wear particle-induced aseptic inflammation is currently unknown. Our experiments were based on metabolomic assay results in a mouse model of aseptic loosening, and studied the function of CD73 in vivo and in vitro using a mouse aseptic loosening model and a mouse bone marrow derived macrophage (BMDM) inflammation model. Results show that aseptic loosening (AL) reduces the purine metabolic pathway and decreases the native expression of the metabolite adenosine. In vivo, CD73 expression was low in the bone tissue surrounding the titanium nail and synovial-like interface tissue, while in vitro experiments demonstrated that CD73 knockdown promoted titanium particles-induced aseptic inflammation. CD73 overexpression mitigated the titanium particle-mediated enhancement of LPS-induced M1 polarization while promoting the titanium particle-mediated attenuation of IL-4-induced M2 polarization. In BMDM exposed to titanium particles, CD73 promotes M2 polarization via the p38 pathway. Meanwhile, local injection of recombinant mouse CD73 protein slightly alleviated the progression of AL. Collectively, our data suggest that CD73 alleviates the process of AL, and this function is achieved by promoting alternate activation of macrophages.

Global scientific trends update on macrophage polarization in rheumatoid arthritis: A bibliometric and visualized analysis from 2000 to 2022

The goal of this work was to use bibliometric analysis to help guide future research on macrophage polarization in RA. We looked for studies on macrophage polarization in RA published between January 1, 2000, and December 31, 2022, in the WoSCC database. Research trends and hotspots were shown and assessed using VOSviewer and CiteSpace. A total of 181 articles were gathered. Belgium was among the early adopters of the field. Chinese institutes have produced the most research. Researchers such as Angel Luis Corb, Amaya Puig-Kröger, and Lizbeth Estrada-Capetillo have made major contributions to the field. Frontiers in Immunology has published the most study findings. According to VOSviewer, the most investigated immune cells, biomarkers, and signaling pathways in the previous three years have been "T cells", "gm-csf", and "nf-κb" in that order. We discovered that the most often used terms in the previous three years were "pathway", "oxidative stress", "extracellular capsule" and "nlrp3 inflammasome" using Citespace. We emphasize these concepts in our findings, presenting the exact mechanisms of pathophysiology related to macrophage polarization in RA, as well as current breakthroughs in therapy strategies.

Photobiomodulation enhances M2 macrophage polarization properties of tonsil-derived mesenchymal stem cells

In this study, the effect of photobiomodulation (PBM) treatment using 630 nm light emitting diode (LED) array (continuous wave type, 10 mW power) on tonsil-derived mesenchymal stem cells (TMSCs) and its interaction with RAW 264.7 macrophage cells via co-culture in vitro were investigated. PBM treatment was used as a priming method for TMSCs to improve therapeutic efficacy. TMSCs were subjected to multi-dose PBM treatments before co-culture with M1 activated (1 μg/mL lipopolysaccharide, LPS) macrophage cells with total energy doses of 0, 15, 30, and 60 J. Irradiation set at 15 J (1500 s treatment time) was performed once, twice for 30 J, and four times for 60 J in an incubator kept at 37 °C and 5% CO2. No significant anti-inflammatory response was observed for TMSCs co-cultured with macrophage cells without PBM. But PBM treatment of TMSCs with 630 nm LED array at 30 J reduced expression of inducible nitric oxide synthase, iNOS (M1) and increased expression of Arginase-1, Arg-1 (M2) phenotype macrophage markers. Anti-inflammatory cytokine interleukin-1 receptor antagonist (IL-1RA) gene expression also increased significantly. Based on the results, PBM priming of TMSCs supports M2 macrophage polarization. PBM can be used to improve the therapeutic efficacy of TMSCs for potential applications in oral mucositis and wound healing.

Biochemical and molecular inducers and modulators of M2 macrophage polarization in clinical perspective

Macrophages as innate immune cells with great plasticity are of great interest for cell therapy. There are two main macrophage populations - pro- and anti-inflammatory cells also known as M1 and M2. High potential in cancer research contributed to the in-depth study of the molecular processes leading to the polarization of macrophages into the M1 phenotype, and much less attention has been paid to anti-inflammatory M2 macrophages, which can be successfully used in cell therapy of inflammatory diseases. This review describes ontogenesis of macrophages, main functions of pro- and and-inflammatory cells and four M2 subpopulations characterized by different functionalities. Data on agents (cytokines, microRNAs, drugs, plant extracts) that may induce M2 polarization through the changes in microenvironment, metabolism, and efferocytosis are summarized. Finally, recent attempts at stable macrophage polarization using genetic modifications are described. This review may be helpful for researchers concerned with the problem of M2 macrophage polarization and potential use of these anti-inflammatory cells for the purposes of regenerative medicine.

Astragaloside IV antagonizes the malignant progression of breast cancer induced by macrophage M2 polarization through the TGF-β-regulated Akt/Foxo1 pathway

BACKGROUND

Astragaloside IV (AS‑IV) was used for breast cancer (BC) treatment in China from ancient times; however, the mechanism of the prevention effect of AS-IV on BC remains not entirely clear.

METHODS

qRT-PCR, western blot and flow cytometry were employed to validate the expression of gene and protein expressions. CCK-8 assay, scratch assay, and transwell assay were used to assess the BC cell proliferation, migration, and invasion. Co-culture of conditional medium from macrophages and BC were performed.

RESULTS

AS-IV suppressed macrophage polarized to M2 phenotype and thereby inhibited M2 macrophage-induced BC progression. The inhibitory effect of AS-IV on M2 macrophage polarization was exerted via the deactivation of the Akt/Foxo1 signaling pathway in macrophages by suppressing TGF-β. The addition of TGF-β or the treatment with Akt activator SC79 reversed the regulatory effect of AS-IV on M2 macrophage polarization, which increased M2 macrophage polarization-induced BC cell proliferation, migration and invasion.

CONCLUSION

This present study revealed a new mechanism of AS-IV inhibited M2 macrophage polarization-induced BC progression and may provide a potential target for the treatment of BC.

Clinical implications and mechanism of complement C1q in polymyositis

Polymyositis (PM) is the most common autoimmune disease in neurology and among muscle disorders; it is of great significance to thoroughly understand the mechanism of PM to find new diagnosis and treatment methods. This research intends to elucidate the clinical implications and mechanisms of complement C1q in polymyositis (PM). One hundred fifteen PM patients (research group, RG) and 120 healthy subjects (control group, CG) who visited our hospital between March 2017 and March 2020 were selected. Peripheral blood C1q and creatine kinase (CK) levels of both groups were measured, and their correlations with clinical symptoms and prognostic recurrence of PM. Additionally, to further understand the mechanism of action of C1q in PM, we purchased BALB/c mice and grouped them as follows: control group with normal feeding, PM group with PM modeling, intervention group with PM modeling, and intraperitoneal injection of gC1qR monoclonal antibody 60.11, a C1q protein receptor. Inflammatory factors and muscle histopathology were detected in all groups of mice. Finally, rat macrophages (mø) were isolated, and changes in the biological behavior of mø were observed after silencing the expression of gC1qR. Serum C1q and CK were both higher in RG than in CG, with favorable diagnostic effects on PM (P < 0.05). C1q and CK increased in symptomatic anti-ribonuclear protein antibody (RNP)-positive patients but decreased in anti Jo-1 antibody (Jo-1)- and anti-neutrophil cytoplasmic antibody (ANCA)-positive patients (P < 0.05). PM mice were observed with elevated gC1qR, while model mice exhibited severe infiltration of inflammatory cells in muscle tissue, increased pro-IFs, and reduced anti-IFs, and the animals in the intervention group showed improved conditions (P < 0.05). Finally, it was found that CD68, CD86 protein, and invasion capacity of gC1qR-sh-transfected cells decreased, while CD206 and CD163 increased (P < 0.05). C1q is elevated in PM and is strongly linked to the pathological process of PM. Inhibition of gC1qR expression reduced inflammatory infiltration in PM mice.

Inhibiting Anti-angiogenic VEGF165b Activates a Novel miR-17-20a-Calcipressin-3 Pathway that Revascularizes Ischemic Muscle in Peripheral Artery Disease

Background

VEGF165a increases the expression of microRNA-17-92 cluster, promoting developmental, retinal, and tumor angiogenesis. We have previously shown that VEGF165b, an alternatively spliced VEGF-A isoform, inhibits the VEGFR-STAT3 pathway in ischemic endothelial cells (ECs) to decrease their angiogenic capacity. In ischemic macrophages (Møs), VEGF165b inhibits VEGFR1 to induce S100A8/A9 expression, which drives M1-like polarization. Our current study aims to determine whether VEGF165b inhibition promotes perfusion recovery by regulating the miR-17-92 cluster in preclinical PAD.

Methods

Hind limb ischemia (HLI) induced by femoral artery ligation and resection was used as a preclinical PAD model. Hypoxia serum starvation (HSS) was used as an in vitro PAD model. VEGF165b was inhibited/neutralized by an isoform-specific VEGF165b antibody.

Results

Systematic analysis of miR-17-92 cluster members (miR-17-18a-19a-19b-20a-92) in experimental-PAD models showed that VEGF165b-inhibition induces miRNA-17-20a (within miR-17-92 cluster) in HSS-ECs and HSS-bone marrow derived macrophages (BMDMs) vs. respective normal and/or isotype matched IgG controls to enhance perfusion-recovery. Consistent with the bioinformatics analysis that revealed RCAN3 as a common target of miR-17 and miR-20a, Argonaute-2 pull-down assays showed decreased miR-17-20a expression and higher RCAN3 expression in the RISC complex of HSS-ECs and HSS-BMDMs vs. the respective controls. Inhibiting miR-17-20a induced RCAN3 levels to decrease ischemic angiogenesis and promoted M1-like polarization to impair perfusion recovery. Finally, using STAT3 inhibitors, S100A8/A9 silencers and VEGFR1-deficient ECs and Møs, we show that VEGF165b inhibition activates the miR-17-20a-RCAN3 pathway independent of VEGFR1-STAT3 or VEGFR1-S100A8/A9 in ischemic ECs and ischemic Møs, respectively.

Conclusion

Our data revealed a hereunto unrecognized therapeutic 'miR-17-20a-RCAN3' pathway in the ischemic vasculature that is VEGFR1-STAT3/S100A8/A9 independent and is activated only upon VEGF165b inhibition in PAD.

Fu-Zheng-Xuan-Fei formula promotes macrophage polarization and Th17/Treg cell homeostasis against the influenza B virus (Victoria strain) infection

ETHNOPHARMACOLOGICAL RELEVANCE

Fu-Zheng-Xuan-Fei formula (FF) is a prescription that has been clinically used through the basic theory of traditional Chinese medicine (TCM) for treating viral pneumonia. Although FF possesses a prominent clinical therapeutic effect, seldom pharmacological studies have been reported on its anti-influenza B virus (IBV) activity.

AIM OF THE STUDY

Influenza is an acute infectious respiratory disease caused by the influenza virus, which has high annual morbidity and mortality worldwide. With a global decline in the COVID-19 control, the infection rate of influenza virus is gradually increasing. Therefore, it is of great importance to develop novel drugs for the effective treatment of influenza virus. Apart from conventional antiviral drugs, TCM has been widely used in the clinical treatment of influenza in China. Therefore, studying the antiviral mechanism of TCM can facilitate the scientific development of TCM.

MATERIALS AND METHODS

Madin-Darby canine kidney cells (MDCK) and BALB/c mice were infected with IBV, and FF was added to evaluate the anti-IBV effects of FF both in vitro and in vivo by Western blotting, immunofluorescence, flow cytometry, and pathological assessment.

RESULTS

It was found that FF exhibited anti-viral activity against IBV infection both in vivo and in vitro, while inducing macrophage activation and promoting M1 macrophage polarization. In addition, FF effectively regulated the signal transducer and activator of transcription (STAT) signaling pathway-mediated Th17/Treg balance to improve the lung tissue damage caused by IBV infection-induced inflammation. The findings provided the scientific basis for the antiviral mechanism of FF against IBV infection.

CONCLUSIONS

This study shows that FF is a potentially effective antiviral drug against IBV infection.

Tau deficiency inhibits classically activated macrophage polarization and protects against collagen-induced arthritis in mice

BACKGROUND

Tau protein serves a pro-inflammatory function in neuroinflammation. However, the role of tau in other inflammatory disorders such as rheumatoid arthritis (RA) is less explored. This study is to investigate the role of endogenous tau and the potential mechanisms in the pathogenesis of inflammatory arthritis.

METHODS

We established collagen-induced arthritis (CIA) model in wild-type and Tau-/- mice to compare the clinical score and arthritis incidence. Micro-CT analysis was used to evaluate bone erosion of ankle joints. Histological analysis was performed to assess inflammatory cell infiltration, cartilage damage, and osteoclast activity in the ankle joints. Serum levels of pro-inflammatory cytokines were measured by ELISA. The expression levels of macrophage markers were determined by immunohistochemistry staining and quantitative real-time PCR.

RESULTS

Tau expression was upregulated in joints under inflammatory condition. Tau deletion in mice exhibited milder inflammation and protected against the progression of CIA, evidenced by reduced serum levels of pro-inflammatory cytokines and attenuated bone loss, inflammatory cell infiltration, cartilage damage, and osteoclast activity in the ankle joints. Furthermore, tau deficiency led to the inhibition of classically activated type 1 (M1) macrophage polarization in the synovium.

CONCLUSION

Tau is a previously unrecognized critical regulator in the pathogenesis of RA and may provide a potential therapeutic target for autoimmune and inflammatory joint diseases.

Vitamin D receptor-deficient keratinocytes-derived exosomal miR-4505 promotes the macrophage polarization towards the M1 phenotype

BACKGROUND

The vitamin D receptor (VDR) has a low level of expression in the keratinocytes of patients with psoriasis and plays a role in the development of the disease. Furthermore, the crosstalk between macrophages and psoriatic keratinocytes-derived exosomes is critical for psoriasis progression. However, the effects of VDR-deficient keratinocytes-derived exosomes (Exos-shVDR) on macrophages and their underlying mechanisms remain largely unknown.

METHODS

VDR-deficient keratinocytes were constructed by infecting HaCaT cells with a VDR-targeting lentivirus, mimicking the VDR-deficient state observed in psoriatic keratinocytes. Exosomes were characterized using transmission electron microscopy, nanoparticle tracking analysis, and Western blot. The effect of Exos-shVDR on macrophage proliferation, apoptosis, and M1/M2 polarization was assessed using cell counting kit-8 assay (CCK-8), flow cytometer, real-time quantitative polymerasechain reaction (RT-qPCR), and enzyme-linked immunosorbent assay (ELISA). The mechanism underlying the effect of Exos-shVDR on macrophage function was elucidated through data mining, bioinformatics, RT-qPCR, and rescue experiments.

RESULTS

Our results revealed that both Exos-shVDR and Exos-shNC exhibited typical exosome characteristics, including a hemispheroid shape with a concave side and particle size ranging from 50 to 100 nm. The levels of expression of VDR were significantly lower in Exos-shVDR than in Exos-shNC. Functional experiments demonstrated that Exos-shVDR significantly promoted macrophage proliferation and polarization towards the M1 phenotype while inhibiting macrophage apoptosis. Moreover, miR-4505 was highly expressed in the skin tissue of patients with psoriasis. Its overexpression significantly increased macrophage proliferation and polarization towards M1 and inhibited apoptosis. Furthermore, the effects of Exos-shVDR on macrophage function occur through miR-4505.

CONCLUSIONS

Exos-shVDR exacerbates macrophage proliferation, promotes polarization towards the M1 phenotype, and inhibits macrophage apoptosis by increasing the levels of miR-4505. These results indicate that modulation of macrophage function is a potential strategy for developing new drugs for the treatment of psoriasis.

Umbilical Cord Blood-Derived Monocytes as A Reliable Source of Functional Macrophages for Biomedical Research

OBJECTIVE

Macrophages are multifunctional immune cells widely used in immunological research. While autologous macrophages have been widely used in several biomedical applications, allogeneic macrophages have also demonstrated similar or even superior therapeutic potential. The umbilical cord blood (UCB) is a well-described source of abundant allogenic monocytes and macrophages that is easy to collect and can be processed without invasive methods. Current monocyte isolation procedures frequently result in heterogenous cell products, with limited yields, activated cells, and high cost. This study outlines a simple isolation method that results in high yields and pure monocytes with the potential to differentiate into functional macrophages.

MATERIALS AND METHODS

In the experimental study, we describe a simple and efficient protocol to isolate highpurity monocytes. After collection of human UCB samples, we used a gradient-based procedure composed of three consecutive gradient steps: i. Hydroxyethyl starch-based erythrocytes sedimentation, followed by ii. Mononuclear cells (MNCs) isolation by Ficoll-Hypaque gradient, and iii. Separation of monocytes from lymphocytes by a slight hyperosmolar Percoll gradient (0.573 g/ml). Then the differentiation potential of isolated monocytes to pro- and antiinflammatory macrophages were evaluated in the presence of granulocyte colony-stimulating factor (GM-CSF) and macrophage CSF (M-CSF), respectively. The macrophages were functionally characterized as well.

RESULTS

A high yield of monocytes after isolation (25 to 50 million) with a high purity (>95%) could be obtained from every 100-150 ml UCB. Isolated monocytes were defined based on their phenotype and surface markers expression pattern. Moreover, they possess the ability to differentiate into pro- or anti-inflammatory macrophages with specific phenotypes, gene/surface protein markers, cytokine secretion patterns, T-cell interactions, and phagocytosis activity.

CONCLUSION

Here we describe a simple and reproducible procedure for isolation of pure monocytes from UCB, which could be utilized to provide functional macrophages as a reliable and feasible source of allogenic macrophages for biomedical research.

Hyaluronic acid modified oral drug delivery system with mucoadhesiveness and macrophage-targeting for colitis treatment

Based on the biocompatibility and macrophage targeting of natural polysaccharides, combined with the physiological and pathological characteristics of the gastrointestinal tract and colonic mucosa of ulcerative colitis (UC), we prepare dexamethasone (Dex)-loaded oral colon-targeted nano-in-micro drug delivery systems coated with multilayers of chitosan (CS), hyaluronic acid (HA), and finally Eudragit S100 (ECHCD MPs) using a layer-by-layer coating technique for UC treatment through regulating the M1/M2 polarization of intestinal macrophages. HA/CS/Dex nanoparticles (HCD NPs) are ingested by macrophages via CD44 receptor-mediated endocytosis to regulate M1-to-M2 macrophage polarization and exert anti-inflammatory effects. Moreover, ECHCD MPs show better colon-targeting properties than Dex-loaded chitosan nanoparticles (CD NPs) and HCD NPs which is demonstrated by stronger mucoadhesion to inflamed colon tissues. After oral administration, ECHCD MPs exert significant anti-UC effects. Therefore, ECHCD MPs are proven to be as promising oral colon-targeting drug delivery systems for Dex and have potential application in UC treatment.