Phyllolobium chinense Fisch Flavonoids (PCFF) Suppresses the M1 Polarization of LPS-Stimulated RAW264.7 Macrophages by Inhibiting NF-κB/iNOS Signaling Pathway

Peek@ZIF-8(CEL) as a Novel Bone Implant for Large Defect Repair and Enhanced Bone Healing via a Long-Term Stable Bioactive Releaser

The repair of large bone defects poses a significant challenge in orthopedics. Polyetheretherketone (PEEK) is a promising bone substitute, while it suffers a lack of bioactivity. Although several studies have been performed to further improve the bioactivities of PEEK by various surface modifications, PEEK offering long-term, multifaceted biofunctionalities remains still desired. In this study, we introduced metal-organic frameworks (MOFs), specifically ZIF-8 loaded with celecoxib (ZIF-8(CEL)), onto the PEEK surface through dopamine adhesion. The resulting PEEK@ZIF-8(CEL) aims to achieve long-term stable release of Zn ions and CEL for enhanced bone integration. Material characterization and biological experiments confirmed the successful integration of ZIF-8(CEL) onto PEEK and its positive biomedical effects, including creating a positive bone immunological environment and promoting bone growth. This study demonstrates the potential of PEEK@ZIF-8(CEL) as a novel repair material for large bone defects, offering a promising alternative in orthopedic applications.

Loss of Bcl-3 regulates macrophage polarization by promoting macrophage glycolysis

M1/M2 macrophage polarization plays an important role in regulating the balance of the microenvironment within tissues. Moreover, macrophage polarization involves the reprogramming of metabolism, such as glucose and lipid metabolism. Transcriptional coactivator B-cell lymphoma-3 (Bcl-3) is an atypical member of the IκB family that controls inflammatory factor levels in macrophages by regulating nuclear factor kappa B pathway activation. However, the relationship between Bcl-3 and macrophage polarization and metabolism remains unclear. In this study, we show that the knockdown of Bcl-3 in macrophages can regulate glycolysis-related gene expression by promoting the activation of the nuclear factor kappa B pathway. Furthermore, the loss of Bcl-3 was able to promote the interferon gamma/lipopolysaccharide-induced M1 macrophage polarization by accelerating glycolysis. Taken together, these results suggest that Bcl-3 may be a candidate gene for regulating M1 polarization in macrophages.

The role of macrophage polarization in tendon healing and therapeutic strategies: Insights from animal models

Tendon injuries, a common musculoskeletal issue, usually result in adhesions to the surrounding tissue, that will impact functional recovery. Macrophages, particularly through their M1 and M2 polarizations, play a pivotal role in the inflammatory and healing phases of tendon repair. In this review, we explore the role of macrophage polarization in tendon healing, focusing on insights from animal models. The review delves into the complex interplay of macrophages in tendon pathology, detailing how various macrophage phenotypes contribute to both healing and adhesion formation. It also explores the potential of modulating macrophage activity to enhance tendon repair and minimize adhesions. With advancements in understanding macrophage behavior and the development of innovative biomaterials, this review highlights promising therapeutic strategies for tendon injuries.

Fabrication and characterization of metformin-loaded PLGA/Collagen nanofibers for modulation of macrophage polarization for tissue engineering and regenerative medicine

In tissue engineering (TE) and regenerative medicine, the accessibility of engineered scaffolds that modulate inflammatory states is extremely necessary. The aim of the current work was to assess the efficacy of metformin (MET) incorporated in PLGA/Collagen nanofibers (Met-PLGA/Col NFs) to modulate RAW264.7 macrophage phenotype from pro-inflammatory status (M1) to anti-inflammatory status (M2). Given this, MET-PLGA/Col NFs were fabricated using an electrospinning technique. Structural characterization such as morphology, chemical and mechanical properties, and drug discharge pattern were assessed. MTT assay test exposed that MET-PLGA/Col NFs remarkably had increased cell survival in comparison with pure PLGA/Collagen NFs and control (p < 0.05) 72 h after incubation. Based on the qPCR assay, a reduction in the expression of iNOS-2 and SOCS3 was found in the cells seeded on MET-PLGA/Col NFs, demonstrating the substantial modulation of the M1 phenotype to the M2 phenotype. Moreover, it was determined a main decrease in the pro-inflammatory cytokines and mediator's expression but the growth factors amount related to anti-inflammatory M2 were meaningfully upregulated. Finally, MET-PLGA/Col NFs possibly will ensure a beneficial potential for effective variation of the macrophage response from an inflammatory phase (M1) to a pro-regenerative (M2) phase.

Oxidative stress following spinal cord injury: From molecular mechanisms to therapeutic targets

Spinal cord injury (SCI) is a medical condition that results from severe trauma to the central nervous system; it imposes great psychological and economic burdens on affected patients and their families. The dynamic balance between reactive oxygen species (ROS) and antioxidants is essential for maintaining normal cellular physiological functions. As important intracellular signaling molecules, ROS regulate numerous physiological activities, including vascular reactivity and neuronal function. However, excessive ROS can cause damage to cellular macromolecules, including DNA, lipids, and proteins; this damage eventually leads to cell death. This review discusses the mechanisms of oxidative stress in SCI and describes some signaling pathways that regulate oxidative injury after injury, with the aim of providing guidance for the development of novel SCI treatment strategies.

Research Progress of Immunomodulation on Anti-COVID-19 and the Effective Components from Traditional Chinese Medicine

SARS-CoV-2 has posed a threat to the health of people around the world because of its strong transmission and high virulence. Currently, there is no specific medicine for the treatment of COVID-19. However, for a wide variety of medicines used to treat COVID-19, traditional Chinese medicine (TCM) plays a major role. In this paper, the effective treatment of COVID-19 using TCM was consulted first, and several Chinese medicines that were frequently used apart from their huge role in treating it were found. Then, when exploring the active ingredients of these herbs, it was discovered that most of them contained flavonoids. Therefore, the structure and function of the potential active substances of flavonoids, including flavonols, flavonoids, and flavanes, respectively, are discussed in this paper. According to the screening data, these flavonoids can bind to the key proteins of SARS-CoV-2, 3CLpro, PLpro, and RdRp, respectively, or block the interface between the viral spike protein and ACE2 receptor, which could inhibit the proliferation of coronavirus and prevent the virus from entering human cells. Besides, the effects of flavonoids on the human body systems are expounded on in this paper, including the respiratory system, digestive system, and immune system, respectively. Normally, flavonoids boost the body's immune system. However, they can suppress the immune system when over immunized. Ultimately, this study hopes to provide a reference for the clinical drug treatment of COVID-19 patients, and more TCM can be put into the market accordingly, which is expected to promote the development of TCM on the international stage.

Shexiang Tongxin Dropping Pill alleviates M1 macrophage polarization-induced inflammation and endothelial dysfunction to reduce coronary microvascular dysfunction via the dectin-1/Syk/IRF5 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Shexiang Tongxin Dropping Pill (STDP), a traditional Chinese medicine compound, is fragrant, invigorates the qi, unblocks pulses, activates the blood circulation, removes blood stasis, and relieves pain. It is used clinically to treat coronary heart disease and angina pectoris. Coronary microvascular dysfunction (CMD) is associated with increased morbidity and mortality from cardiovascular events. Endothelial dysfunction and inflammation have been verified as its underlying causes. STDP can ameliorate CMD, but the mechanism has not been fully elucidated.

AIM OF THE STUDY

To explore the effects of STDP on M1 macrophage polarization-induced inflammation and endothelial dysfunction as an inhibitor of CMD, and to determine its mechanisms of action.

MATERIALS AND METHODS

The CMD rat model was established by left anterior descending artery (LAD) ligation. The efficacy of STDP against CMD was evaluated by echocardiography, optical microangiography, Evans blue staining, and histological examination. The OGD/R-induced endothelial injury model, the endothelial injury-induced sterile inflammation model, the Dectin-1 overexpression model, and the Dectin-1-overexpressing RAW264.7 macrophage supernatant-stimulated HUVEC-induced secondary injury of endothelial function model were established to confirm the efficacy of STDP against M1 macrophage polarization-induced inflammation and endothelial dysfunction.

RESULTS

STDP blunted the deterioration of cardiac function and ameliorated CMD by reducing inflammatory cell infiltration and endothelial dysfunction in CMD rats. Endothelial injury and Dectin-1 overexpression induced M1 macrophage polarization and inflammation. Mechanically, STDP hindered M1 macrophage polarization and inflammation by inhibiting the Dectin-1/Syk/IRF5 pathway both in vivo and in vitro. STDP alleviated endothelial dysfunction induced by Dectin-1 overexpression in macrophages.

CONCLUSION

STDP can alleviate M1 macrophage polarization-induced inflammation and endothelial dysfunction against CMD via the Dectin-1/Syk/IRF5 pathway. Dectin-1-associated M1 macrophage polarization might be developed as a novel target for ameliorating CMD.

Neu1 deficiency increases the susceptibility of zebrafish to Edwardsiella piscicida infection via lysosomal dysfunction

Neu1 is a lysosomal glycosidase that catalyzes the removal of sialic acids from glycoconjugates. Although Neu1 sialidase is highly conserved among vertebrates, the role of fish Neu1 is not fully understood because of its unique aquatic living situation. Compared to land animals, fish have a higher chance of bacterial infection, and to understand the role of fish Neu1, the susceptibility of Neu1 knockout zebrafish (Neu1-KO) was evaluated using Edwardsiella piscicida, a fish pathogen. Neu1-KO larvae showed high susceptibility to E. piscicida, despite the activation of macrophages, and presented increased lysosomal signals induced by the accumulation of Sia α2-3 linked oligosaccharides. The accumulation coincided with the signal of the macrophage marker, suggesting that the dysfunction of lysosomes in macrophages would result in a high susceptibility of Neu1-KO to E. piscicida. Chloroquine, an inhibitor of lysosomal degradation, induced high mortality of wild type zebrafish with E. piscicida infection accompanied by increased lysosomal accumulation, similar to Neu1-KO zebrafish. This study revealed that Neu1 sialidase plays a crucial role in the lysosomal degradation of macrophages with a bacterial infection.

Macrophage Polarization Modulated by NF-κB in Polylactide Membranes-Treated Peritendinous Adhesion

Foreign body reactions (FBR) to implants seriously impair tissue-implant integration and postoperative adhesion. The macrophage, owing to its phenotypic plasticity, is a major regulator in the formation of the inflammatory microenvironment; NF-κB signaling also plays a vital role in the process. It is hypothesized that NF-κB phosphorylation exerts a proinflammatory regulator in FBR to polylactide membranes (PLA-M) and adhesion. First, in vitro and in vivo experiments show that PLA-M induces NF-κB phosphorylation in macrophages, leading to M1 polarization and release of inflammatory factors. The inflammatory microenvironment formed due to PLA-M accelerates myofibroblast differentiation and release of collagen III and MMP2, jointly resulting in peritendinous adhesion. Therefore, JSH-23 (a selective NF-κB inhibitor)-loaded PLA membrane (JSH-23/PLA-M) is fabricated by blend electrospinning to regulate the associated M1 polarization for peritendinous anti-adhesion. JSH-23/PLA-M specifically inhibits NF-κB phosphorylation in macrophages and exhibits anti-inflammatory and anti-adhesion properties. The findings demonstrate that NF-κB phosphorylation has a critical role in PLA-induced M1 polarization and aggravating FBR to PLA-M. Additionally, JSH-23/PLA-M precisely targets modulation of NF-κB phosphorylation in FBR to break the vicious cycle in peritendinous adhesion therapy.

M1 macrophages impair tight junctions between endothelial cells after spinal cord injury

After spinal cord injury (SCI), endogenous angiogenesis occurs in the injury core, unexpectedly accompanied by continuous leakage of the blood-spinal cord barrier (BSCB), which may be caused by destruction of the tight junctions (TJs) between vascular endothelial cells-an important structure of the BSCB. Blood-derived macrophages infiltrate into the spinal cord, aggregate to the injury core and then polarize toward M1/M2 phenotypes after SCI. However, the effect of macrophages with different polarizations on the TJs between vascular endothelial cells remains unclear. Here, we demonstrated that from 7 days postinjury (dpi) to 28 dpi, accompanied by the aggregation of macrophages, the expression of claudin-5 (CLN-5) and zonula occludens-1 (ZO-1) in vascular endothelial cells in the injury core was significantly decreased in comparison to that in normal spinal cord tissue and in the penumbra. Moreover, the leakage of the BSCB was severe in the injury core, as demonstrated by FITC-dextran perfusion. Notably, our study demonstrated that depletion of macrophages facilitated the restoration of TJs between vascular endothelial cells and decreased the leakage of BSCB in the injury core after SCI. Furthermore, we confirmed that the endothelial TJs could be impaired by M1 macrophages through secreting IL-6 in vitro, leading to an increased permeability of endothelial cells, but it was not significantly affected by M0 and M2 macrophages. These results indicated that the TJs between vascular endothelial cells were impaired by M1 macrophages in the injury core, potentially resulting in continuous leakage of the BSCB after SCI. Preventing M1 polarization of macrophages or blocking IL-6 in the injury core may promote restoration of the BSCB, thus accelerating functional recovery after SCI.

Macrophage Reprogramming and Cancer Therapeutics: Role of iNOS-Derived NO

Nitric oxide and its production by iNOS is an established mechanism critical to tumor promotion or suppression. Macrophages have important roles in immunity, development, and progression of cancer and have a controversial role in pro- and antitumoral effects. The tumor microenvironment consists of tumor-associated macrophages (TAM), among other cell types that influence the fate of the growing tumor. Depending on the microenvironment and various cues, macrophages polarize into a continuum represented by the M1-like pro-inflammatory phenotype or the anti-inflammatory M2-like phenotype; these two are predominant, while there are subsets and intermediates. Manipulating their plasticity through programming or reprogramming of M2-like to M1-like phenotypes presents the opportunity to maximize tumoricidal defenses. The dual role of iNOS-derived NO also influences TAM activity by repolarization to tumoricidal M1-type phenotype. Regulatory pathways and immunomodulation achieve this through miRNA that may inhibit the immunosuppressive tumor microenvironment. This review summarizes the classical physiology of macrophages and polarization, iNOS activities, and evidence towards TAM reprogramming with current information in glioblastoma and melanoma models, and the immunomodulatory and therapeutic options using iNOS or NO-dependent strategies.

Recent advancement on development of drug-induced macrophage polarization in control of human diseases

Macrophages, an important part of human immune system, possess a high plasticity and heterogeneity (macrophage polarization) as classically activated macrophages (M1) and alternatively activated macrophages (M2), which exert pro-inflammatory/anti-tumor and anti-inflammatory/pro-tumor effects, respectively. Thus, drug development in induction of macrophage polarization could be used to treat different human diseases. This review summarizes the recent advancement on modulation of macrophage polarization and its related molecular mechanisms induced by a number of agents. Research on the anti-inflammatory drugs to regulate the macrophage polarization accounts for a large proportion in the field and types of diseases investigated could include atherosclerosis, enteritis, nephritis, and the nervous system and skeletal diseases, while study of the anti-tumor agents to modify macrophage polarization is a novel area of research. Future study of the molecular mechanisms by which the different agents regulate the macrophage polarization could lead to an effective control of various human diseases, including inflammation and cancers.

A Systematic Study of the Mechanism of Acacetin Against Sepsis Based on Network Pharmacology and Experimental Validation

Sepsis is a dysregulated systemic response to infection, and no effective treatment options are available. Acacetin is a natural flavonoid found in various plants, including Sparganii rhizoma, Sargentodoxa cuneata and Patrinia scabiosifolia. Studies have revealed that acacetin potentially exerts anti-inflammatory and antioxidative effects on sepsis. In this study, we investigated the potential protective effect of acacetin on sepsis and revealed the underlying mechanisms using a network pharmacology approach coupled with experimental validation and molecular docking. First, we found that acacetin significantly suppressed pathological damage and pro-inflammatory cytokine expression in mice with LPS-induced fulminant hepatic failure and acute lung injury, and in vitro experiments further confirmed that acacetin attenuated LPS-induced M1 polarization. Then, network pharmacology screening revealed EGFR, PTGS2, SRC and ESR1 as the top four overlapping targets in a PPI network, and GO and KEGG analyses revealed the top 20 enriched biological processes and signalling pathways associated with the therapeutic effects of acacetin on sepsis. Further network pharmacological analysis indicated that gap junctions may be highly involved in the protective effects of acacetin on sepsis. Finally, molecular docking verified that acacetin bound to the active sites of the four targets predicted by network pharmacology, and in vitro experiments further confirmed that acacetin significantly inhibited the upregulation of p-src induced by LPS and attenuated LPS-induced M1 polarization through gap junctions. Taken together, our results indicate that acacetin may protect against sepsis via a mechanism involving multiple targets and pathways and that gap junctions may be highly involved in this process.

The response of two polar monocyte subsets to inflammation

Macrophages are a central component of innate immunity that play an important role in the defense of the organism. Macrophages are highly plastic and are activated by interaction with other cells and environmental factors. In this work, we study the effect of lipopolysaccharide on macrophages derived from the two most polar (CD14+ and CD16+ monocytes) as well as the intermediate subset of blood monocytes from healthy donors and assess what happens to the subset most prone to polarization on the transcriptomic and proteomic level. It has been shown that, according to primary pro-inflammatory polarization markers, their cytokine profile, and their phagocytic activity, macrophages derived from CD14+ monocytes exhibit higher sensitivity to inducers of pro-inflammatory polarization. Flow cytometry analysis revealed increased levels of CD86, while secretome analysis demonstrated significant increase of pro-inflammatory and anti-inflammatory cytokines observed in CD14+-derived macrophages, as compared to CD16+-derived macrophages in conditioned media. Assessment of the transcriptome and proteome of CD14+-derived macrophages with further bioinformatic analysis identified the most significant differences after polarization towards the pro-inflammatory phenotype. Immune-, membrane-, IFN-γ-, cytokine-, and defense-associated pathways were found significantly prevalent, while downregulated pathways were represented by RNA binding-, housekeeping-, exocytosis-, intracellular transport-, peptide and amide metabolic-related signaling. This data could be useful for macrophage-based cell therapeutics of cancer, as it provides additional background for the manipulation of donor monocytes intended for back transplantation.

Pseudolaric acid B ameliorates synovial inflammation and vessel formation by stabilizing PPARγ to inhibit NF-κB signalling pathway

Synovial macrophage polarization and inflammation are essential for osteoarthritis (OA) development, yet the molecular mechanisms and regulation responsible for the pathogenesis are still poorly understood. Here, we report that pseudolaric acid B (PAB) attenuated articular cartilage degeneration and synovitis during OA. PAB, a diterpene acid, specifically inhibited NF-κB signalling and reduced the production of pro-inflammatory cytokines, which further decreased M1 polarization and vessel formation. We further provide in vivo and in vitro evidences that PAB suppressed NF-κB signalling by stabilizing PPARγ. Using PPARγ antagonist could abolish anti-inflammatory effect of PAB and rescue the activation of NF-κB signalling during OA. Our findings identify a previously unrecognized role of PAB in the regulation of OA and provide mechanisms by which PAB regulates NF-κB signalling through PPARγ, which further suggest targeting synovial inflammation or inhibiting vessel formation at early stage could be an effective preventive strategy for OA.

M2 Macrophages Promote PDGFRβ+ Pericytes Migration After Spinal Cord Injury in Mice via PDGFB/PDGFRβ Pathway

Platelet derived growth factor receptor β positive (PDGFRβ⁺) pericytes form fibrotic scar, which prevents axonal regeneration after spinal cord injury (SCI). However, the mechanism by which PDGFRβ⁺ pericytes migrate to the injury core is unclear. Here, we investigated the effect and mechanism of macrophages polarization on PDGFRβ⁺ pericytes migration after SCI. Macrophages were closely related to the spatiotemporal distribution of PDGFRβ⁺ pericytes in the injury core at 3, 7, and 14 days postinjury (dpi). Macrophages appeared M2 polarization at 3 and 7 dpi while M1 polarization at 14 dpi. The expression of platelet derived growth factor B (PDGFB) was significantly increased after SCI and after macrophages M2 polarization. The promoting effect of exogenous PDGFB and M2 macrophages conditioned medium on PDGFRβ⁺ pericytes migration could be blocked by SU16f, a PDGFRβ specific inhibitor. These findings indicate that M2 macrophages can secrete PDGFB acting on PDGFRβ to promote PDGFRβ⁺ pericytes migration, which can be blocked by a PDGFRβ specific inhibitor SU16f. The PDGFB/PDGFRβ pathway is a promising new target for the treatment of SCI.

Artocarpus tonkinensis Extract Inhibits LPS-Triggered Inflammation Markers and Suppresses RANKL-Induced Osteoclastogenesis in RAW264.7

Artocarpus tonkinensis (At) leaf decoction, a traditional remedy prepared in North Vietnam by the Hmong ethnic group, is a tea extract rich in bioactive compounds that may have therapeutic effects in arthritis and backache. Indeed, it has been demonstrated that At is able to inhibit Th17 lymphocytes development and to protect mice in an experimental model of collagen-induced arthritis. By resorting to macrophage in vitro models of inflammation and osteoclastogenesis, we showed that At extract significantly reduced nitric oxide synthase 2 (NOS2) activity and IL-6 production by RAW 264.7 murine cells. Moreover, At demonstrated an anti-osteoclastogenic effect, as revealed by complete inhibition of TRAP-positive osteoclast formation and decreased expression of key osteoclast-related genes. This At activity likely relies on the inhibition of RANK downstream signaling pathway, as the activation of non-receptor tyrosine kinase Src is reduced upon RANKL-At exposure. Protective effect of At against bone loss was also enlightened in vivo by collagen-induced arthritis (CIA) experiment demonstrating that, although paw edema was only weakly opposed by drinking At decoction, bone and cartilage were well preserved in CIA+At mice and joint tissue expressed decreased levels of osteoclast marker genes respect to CIA control group. Maesopsin 4-O-β-D-glucoside (i.e., TAT-2, one of the main decoction bioactive components) was capable to contrast NOS2 activity, IL-6 expression and osteoclast formation, too, albeit to a lesser extent when compared to At decoction. Overall, this study enlightens another At cell target, macrophages, beside Th17 lymphocytes, and suggests that the anti-arthritic beneficial effects of At decoction largely derives from its ability to counteract not only inflammation, but also osteoclastogenesis.