Suppressed testicular macrophage M1 polarization by HDAC5 enforces insensitivity to LPS-elicited blood-testis barrier damage.

Infertility caused by lipopolysaccharide (LPS) exposure due to infection is endangering male fertility worldwide, but the mechanism remains unclear. The blood-testis barrier (BTB) is essential for maintaining spermatogenesis and male fertility. In the present study, we showed that LPS (5.0 mg/kg) treatment markedly down-regulated the expression of BTB-related proteins, expanded the biotin penetration distance and caused histopathological injury in seminiferous tubules in mouse testes. Notably, testicular macrophage M1 polarization induced by LPS seems to be related to BTB damage, which was well confirmed by co-culture of RAW264.7 and TM4 cells in vitro. Interestingly, a low-dose LPS (0.1 mg/kg) pretreatment attenuated down-regulation of BTB-related proteins expression and histopathological injury and shorten biotin penetration distance in seminiferous tubules caused by LPS. Correspondingly, a low-dose LPS pretreatment suppresses testicular macrophage M1 polarization induced by LPS in mouse testes. Further experiments revealed that histone deacetylase 5 (HDAC5) was markedly down-regulated at 2 h and slightly down-regulated at 8 h, but up-regulated at 24 h in mouse testes after LPS treatment. Additionally, low-dose LPS pretreatment against the down-regulation of HDAC5 protein caused by LPS treatment. Notably, the suppressed testicular macrophage M1 polarization by low-dose LPS pretreatment was broken by BRD4354, a specific inhibitor of HDAC5 in vitro. These results suggest suppressed testicular macrophage M1 polarization by HDAC5 enforces insensitivity to LPS-elicited BTB damage.

Polystyrene nanoplastics of different particle sizes regulate the polarization of pro-inflammatory macrophages.

Microplastics (MPs) are defined as plastic particles smaller than 5 mm in size, and nanoplastics (NPs) are those MPs with a particle size of less than 1000 nm or 100 nm. The prevalence of MPs in the environment and human tissues has raised concerns about their potential negative effects on human health. Macrophages are the major defence against foreign substances in the intestine, and can be polarized into two types: the M1 phenotype and the M2 phenotype. However, the effect of NPs on the polarization of macrophages remains unclear. Herein, we selected polystyrene, one of the most plastics in the environment and controlled the particle sizes at 50 nm and 500 nm respectively to study the effects on the polarization of macrophages. We used mouse RAW264.7 cell line models in this macrophage-associated study. Experiments on cell absorption showed that macrophages could quickly ingest polystyrene nanoplastics of both diameters with time-dependent uptake. Compared to the untreated group and 10 µg/mL treatment group, macrophages exposed to 50 µg/mL groups (50 nm and 500 nm) had considerably higher levels of CD86, iNOS, and TNF-α, but decreased levels of aCD206, IL-10, and Arg-1. According to these findings, macrophage M1 and M2 polarization can both be induced and inhibited by 50 µg/mL 50 nm and 500 nm polystyrene nanoplastics. This work provided the first evidence of a possible MPs mode of action with appropriate concentration and size through the production of polarized M1, providing dietary and environmental recommendations for people, particularly those with autoimmune and autoinflammatory illnesses.

Carboxymethyl cellulose/quaternized chitosan hydrogel loaded with polydopamine nanoparticles promotes spinal cord injury recovery by anti-ferroptosis and M1/M2 polarization modulation.

Spinal cord injury (SCI) represents a catastrophic neurological condition resulting in long-term loss of motor, autonomic, and sensory functions. Recently, ferroptosis, an iron-regulated form of cell death distinct from apoptosis, has emerged as a potential therapeutic target for SCI. In this study, we developed an injectable hydrogel composed of carboxymethyl cellulose (CMC), and quaternized chitosan (QCS), loaded with modified polydopamine nanoparticles (PDA NPs), referred to as CQP hydrogel. This hydrogel effectively scavenged reactive oxygen species (ROS), prevented the accumulation of Fe2+ and lipid peroxidation associated with ferroptosis, and restored mitochondrial functions in primary neuronal cells. When administered to animal models (rats) with SCI, the CQP hydrogels improved motor function by regulating iron homeostasis, inhibiting ferroptosis, and mitigating oxidative stress injury. Both in vitro and in vivo studies corroborated the capacity of CQP hydrogels to promote the shift from M1 to M2 polarization of microglia/macrophages. These findings suggest that CQP hydrogels, functioning as a localized iron-chelating system, have potential as biomaterials to enhance recovery from SCI by targeting ferroptosis and modulating anti-inflammatory macrophages activity.

Protective role of macrophages from maternal-fetal interface in unvaccinated coronavirus disease 2019 pregnant women.

Pregnant women represent a high-risk population for Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection. The presence of SARS-CoV-2 has been reported in placenta from infected pregnant women, but whether the virus influences placenta immune response remains unclear. We investigated the properties of maternal-fetal interface macrophages (MFMs) in a cohort of unvaccinated women who contracted coronavirus disease 2019 (COVID-19) during their pregnancy. We reported an infiltration of CD163+ macrophages in placenta from COVID-19 women 19 whereas lymphoid compartment was not affected. Isolated MFMs exhibited nonpolarized activated signature (NOS2, IDO1, IFNG, TNF, TGFB) mainly in women infected during the second trimester of pregnancy. COVID-19 during pregnancy primed MFM to produce type I and III interferon response to SARS-CoV-2 (Wuhan and δ strains), that were unable to elicit this in MFMs from healthy pregnant women. COVID-19 also primed SARS-CoV-2 internalization by MFM in an angiotensin-converting enzyme 2-dependent manner. Activation and recall responses of MFMs were influenced by fetal sex. Collectively, these findings support a role for MFMs in the local immune response to SARS-CoV-2 infection, provide a basis for protective placental immunity in COVID-19, and highlight the interest of vaccination in pregnant women.

Adipose tissue-selective ablation of ADAM10 results in divergent metabolic phenotypes following long-term dietary manipulation.

A Disintegrin And Metalloproteinase domain-containing protein 10 (ADAM10), is involved in several metabolic and inflammatory pathways. We speculated that ADAM10 plays a modulatory role in adipose tissue inflammation and metabolism. To this end, we studied adipose tissue-specific ADAM10 knock-out mice (aKO). While young, regular chow diet-fed aKO mice showed increased insulin sensitivity, following prolonged (33 weeks) high-fat diet (HFD) exposure, aKO mice developed obesity and insulin resistance. Compared to controls, aKO mice showed less inflammatory adipokine profile despite the significant increase in adiposity. In brown adipose tissue, aKO mice on HFD had changes in CD8+ T cell populations indicating a lesser inflammatory pattern. Following HFD, both aKO and control littermates demonstrated decreased adipose tissue pro-inflammatory macrophages, and increased anti-inflammatory accumulation, without differences between the genotypes. Collectively, our observations indicate that selective deletion of ADAM10 in adipocytes results in a mitigated inflammatory response, leading to increased insulin sensitivity in young mice fed with regular diet. This state of insulin sensitivity, following prolonged HFD, facilitates energy storage resulting in increased fat accumulation which ultimately leads to the development of a phenotype of obesity and insulin resistance. In conclusion, the data indicate that ADAM10 has a modulatory effect of inflammation and whole-body energy metabolism.

Lactobacillus Plantarum intake mitigates neuropathic pain behavior via enhancing macrophage M2 polarization in a rat model of peripheral neuropathy.

Pro-inflammatory macrophages (M1-polarized) play a crucial role in neuroinflammation and neuropathic pain following nerve injury. Redirecting macrophage polarization toward anti-inflammatory (M2-polarized) phenotypes offers a promising therapeutic strategy. Recognized for their anti-inflammatory and immunomodulatory properties, probiotics are becoming a focal point of research. This study investigated the effects of Lactobacillus plantarum on macrophage polarization, nerve protection, and neuropathic pain behavior following chronic constriction injury (CCI) of the median nerve. Rats received daily oral doses of L. plantarum for 28 days before and 14 days after CCI. Subsequently, behavioral and electrophysiological assessments were performed. The M1 marker CD86 levels, M2 marker CD206 levels, and concentrations of pro-inflammatory and anti-inflammatory cytokines in the injured median nerve were assessed. L. plantarum administration effectively reduced neuropathic pain behavior and the Firmicutes to Bacteroidetes ratio after CCI. Moreover, L. plantarum treatment increased serum short-chain fatty acids (SCFAs) levels, preserved myelination of the injured median nerve, and suppressed injury-induced discharges. In CCI rats treated with L. plantarum, there was a reduction in CD86 and pro-inflammatory cytokine levels, accompanied by an increase in CD206 and the release of anti-inflammatory cytokines. Furthermore, receptors for anti-inflammatory cytokines were localized on Schwann cells, and their expression was significantly upregulated in the injured nerves of CCI rats receiving L. plantarum. In conclusion, L. plantarum shifts macrophage phenotypes from M1 to M2 by promoting the production of SCFAs and enhancing the release of anti-inflammatory cytokines. Ultimately, this process preserves nerve fiber integrity and impedes the onset of neuropathic pain.

Recent advances in neuroinflammation prevention and therapy: the role of natural products and underlying mechanisms based on molecular targets.

Neuroinflammation is initiated in response to a variety of endogenous and exogenous sources. As the resident macrophages of the central nervous system, the polarization of microglia into either the M1 pro-inflammatory phenotype or the M2 anti-inflammatory phenotype holds great promise as a therapeutic strategy for neuroinflammation. Natural products, comprising a vital chemical library with distinctive structures and diverse functions, have been extensively employed to modulate microglial polarization for the treatment of neuroinflammation. In this review, we present up-to-date and extensive insights into the therapeutic effects and underlying mechanisms of natural products in the context of neuroinflammation. Furthermore, the review aims to present a new perspective by focusing on the targets of natural compounds, elucidating the molecular mechanisms and guiding the transition from natural-derived lead compounds to potential anti-neuroinflammatory drugs. Additionally, we provide a comprehensive overview of the challenges and limitations associated with the utilization of natural products for neuroinflammation therapy.

Calcitriol restrains microglial M1 polarization and alleviates dopaminergic degeneration in hemiparkinsonian mice by boosting regulatory T-cell expansion.

OBJECTIVE: Vitamin D deficiency is a risk factor for Parkinson's disease (PD) and vitamin D supplementation robustly alleviates neurodegeneration in PD models. However, the mechanisms underlying this effect require further clarification. Current evidence suggests that harnessing regulatory T cells (Treg) may mitigate neuronal degeneration. In this study, we investigated the therapeutic effects of vitamin D receptor activation by calcitriol on PD, specifically focusing on its role in Treg. METHODS: Hemiparkinsonian mice model was established through the injection of 6-OHDA into the striatum. Mice were pretreated with calcitriol before 6-OHDA injection. The motor performance, dopaminergic neuronal survival, contents of dopamine, and dopamine metabolites were evaluated. The pro-inflammatory cytokines levels, T-cell infiltration, mRNA expression of indicated microglial M1/M2 phenotypic markers, and microglial marker in the midbrain were detected. Populations of Treg in the splenic tissues were assessed using a flow cytometry assay. PC61 monoclonal antibody was applied to deplete Treg in vivo. RESULTS: We show that calcitriol supplementation notably improved motor performance and reduced dopaminergic degeneration in the 6-OHDA-induced PD model. Mechanistically, calcitriol promoted anti-inflammatory/neuroprotective Treg and inhibited pro-inflammatory/neurodestructive effector T-cell generation in this model. This process significantly inhibited T-cell infiltration in the midbrain, restrained microglial activation, microglial M1 polarization, and decreased pro-inflammatory cytokines release. This more favorable inflammatory microenvironment rescued dopaminergic degeneration. To further verify that the anti-inflammatory effects of calcitriol are associated with Treg expansion, we applied an antibody-mediated Treg depletion assay. As predicted, the anti-inflammatory effects of calcitriol in the PD model were diminished following Treg depletion. CONCLUSION: These findings suggest that calcitriol's anti-inflammatory and neuroprotective effects in PD are associated with its potential to boost Treg expansion.

The effect of Jian Gan powder on the proliferation, migration and polarization of macrophages and relative mechanism.

CONTEXT: Jian Gan powder (JGP) is a Chinese medicine compound comprised ginseng, Radix Paeoniae Alba, Radix Astragali, Salvia miltiorrhiza, Yujin, Rhizoma Cyperi, Fructus aurantii, Sophora flavescens, Yinchen, Bupleurum and licorice. OBJECTIVE: This study explored the inhibitory effects, polarization and potential mechanisms associated with JGP in macrophages. MATERIALS AND METHODS: RAW264.7 cells were randomly divided into six groups for 24 h: control, lipopolysaccharide (LPS), overexpression, 1% JGP, 2% JGP, 4% JGP, 8% JGP and 16% JGP. The effects of JGP on RAW264.7 cell proliferation were assessed using colony formation assays and cell counting kit-8 (CCK-8) assays. The Transwell assay was used to evaluate its impact on RAW264.7 cell migration. Moreover, we analysed the interleukin-6 (IL-6)/signal transducer and activator of the transcription 3 (IL-6/STAT3) signaling pathway using quantitative real-time PCR and Western blotting. Furthermore, we examined the M1/M2 polarization levels. RESULTS: Unlike LPS stimulation, JGP serum treatment markedly suppressed macrophage proliferation and migration capacity, while STAT3 overexpression enhanced RAW264.7 cell proliferation and migration. JGP inhibited the proliferation and migration of RAW264.7 cells by attenuating the IL-6/STAT3 signaling pathway. Furthermore, it inhibited macrophage M1 polarization, promoting M2 polarization. DISCUSSION AND CONCLUSIONS: JGP effectively suppressed the cellular function of RAW264.7 cells by down-regulating the IL-6/STAT3 signaling pathway and modulating macrophage M1/M2 polarization. These findings provide valuable theoretical and experimental basis for considering the potential clinical application of JGP in the treatment of immune-mediated liver injury in clinical practice.

Metabotropic Glutamate Receptor 8 Suppresses M1 Polarization in Microglia by Alleviating Endoplasmic Reticulum Stress and Mitochondrial Dysfunction.

BACKGROUND: Microglia-mediated neuroinflammation is a hallmark of neurodegeneration. Metabotropic glutamate receptor 8 (GRM8) has been reported to promote neuronal survival in neurodegenerative diseases, yet the effect of GRM8 on neuroinflammation is still unclear. Calcium overload-induced endoplasmic reticulum (ER)-mitochondrial miscommunication has been reported to trigger neuroinflammation in the brain. The aim of this study was to investigate putative anti-inflammatory effects of GRM8 in microglia, specifically focusing on its role in calcium overload-induced ER stress and mitochondrial dysfunction. METHODS: BV2 microglial cells were pretreated with GRM8 agonist prior to lipopolysaccharide administration. Pro-inflammatory cytokine levels and the microglial polarization state in BV2 cells were then quantified. Cellular apoptosis and the viability of neuron-like PC12 cells co-cultured with BV2 cells were examined using flow cytometry and a Cell Counting Kit-8, respectively. The concentration of cAMP, inositol-1,4,5-triphosphate receptor (IP3R)-dependent calcium release, ER Ca2+ concentration, mitochondrial function as reflected by reactive oxygen species levels, ATP production, mitochondrial membrane potential, expression of ER stress-sensing protein, and phosphorylation of the nuclear factor kappa B (NF-κB) p65 subunit were also quantified in BV2 cells. RESULTS: GRM8 activation inhibited pro-inflammatory cytokine release and shifted microglia polarization towards an anti-inflammatory-like phenotype in BV2 cells, as well as promoting neuron-like PC12 cell survival when co-cultured with BV2 cells. Mechanistically, microglial GRM8 activation significantly inhibited cAMP production, thereby desensitizing the IP3R located within the ER. This process markedly limited IP3R-dependent calcium release, thus restoring mitochondrial function while inhibiting ER stress and subsequently deactivating NF-κB signaling. CONCLUSIONS: Our results indicate that GRM8 activation can protect against microglia-mediated neuroinflammation by attenuating ER stress and mitochondrial dysfunction, and that IP3R-mediated calcium signaling may play a vital role in this process. GRM8 may thus be a potential target for limiting neuroinflammation.

Knockdown of BCL-3 Attenuates Inflammatory Response in Intracerebral Hemorrhage Through an rBMECs/MGs Microenvironment.

Intracerebral hemorrhage (ICH) is a severe disease with high mortality. Recently, the role of BCL-3 in ICH has started to gain attention, but its mechanism remains unclear. A collagenase injection method was used to establish an ICH model in rats, and the expression of BCL-3 were detected. Rat brain microvascular endothelial cells (rBMECs) were isolated and induced with Hemin to establish an in vitro ICH model. The expression of BCL-3 was assessed, followed by detection of cell apoptosis. In the cell model, the recruitment, polarization, and pro-inflammatory features of the microglia (MGs) were assessed after co-cultured with rBMECs. Finally, in the ICH animal model, after knockdown of BCL-3, comprehensive evaluations of inflammatory responses in brain tissue, polarization and recruitment of microglia, and apoptosis were conducted. Results revealed an upregulated expression of BCL-3 in brain tissue of the ICH animal model. In Hemin-treated rBMECs, an upward trend in BCL-3 expression was observed, accompanied by an increase of cell apoptosis. After co-culturing with the in vitro model, microglia exhibited enhanced M1 polarization and intensified inflammatory responses. However, when BCL-3 expression was inhibited in the in vitro model, a reversal occurred in the polarization tendency and inflammatory responses of microglia. Additionally, after knockdown of BCL-3 in the animal model, notable improvements occurred in M1 polarization, infiltration of macrophages, and inflammatory reactions in the brain tissue. Therefore, BCL-3 modulates the inflammatory response after ICH occurrence through the BMECs/MGs microenvironment. Additionally, BCL-3 might be a potential therapeutic target for ICH management.

Xinyang tablet ameliorates sepsis-induced myocardial dysfunction by regulating Beclin-1 to mediate macrophage autophagy and M2 polarization through LncSICRNT1 targeting E3 ubiquitin ligase TRAF6.

OBJECTIVE: Xinyang Tablet (XYT) has emerged as a potential intervention to counter sepsis-induced myocardial dysfunction (SMID) by influencing macrophage autophagy and M2 polarization. This study aimed to unravel the underlying mechanism of XYT in sepsis-induced myocardial dysfunction (SIMD). METHODS: A microarray analysis was employed to explore sepsis-related changes, and bioinformatics analysis was used to predict lncRNAs binding to tumor necrosis factor receptor-associated factor 6 (TRAF6). This studio utilized SIMD mouse models induced by lipopolysaccharide (LPS) injection, followed by treatments involving varied doses of XYT, digoxin (positive control), or si-LncSICRNT1. After seven days, evaluations encompassing mouse hair/mental state/diet/weight were measured, and cardiac function via echocardiography were conducted. Myocardial tissue changes were observed using hematoxylin-eosin staining. Additionally, bone marrow-derived macrophages (BMDMs) subjected to LPS for M1 polarization were treated with oe-LncSICRNT1, si-TRAF6 and their negative control, XYT, or autophagy inhibitor 3-Methyladenine (3-MA) (positive control). RT-qPCR and Western blot analyses were employed to assess LncSICRNT1, TRAF6, Beclin-1, LC3II/LC3I, and p62 levels. Immunohistochemistry and flow cytometry were used for M1/M2 polarization markers, while enzyme-linked immunosorbent assay (ELISA) gauged inflammatory factor levels. Interaction between TRAF6 and LncSICRNT1 was probed using RNA pull-down and RNA immunoprecipitation (RIP) assays. RESULTS: Chip analysis obtained 1463 differentially expressed lncRNAs, including LINC01550 (LncSICRNT1). Further prediction indicated that LncSICRNT1 was highly likely to directly bind to TRAF6. XYT treatment in LPS-induced SIMD mice led to notable enhancements in sleep/hair/diet/activity, increased weight/left ventricular end-diastolic diameter (LVEDd)/LV ejection fraction (LVEF)/LV fraction shortening (LVFS). These improvements were associated with elevated LncSICRNT1 expression and decreased TRAF6 protein levels, culminating in reduced myocardial inflammatory responses and improved cardiac function. Notably, XYT was found to suppress macrophage M1 polarization, while enhancing M2 polarization, ultimately benefitting cardiac function via LncSICRNT1 modulation. Furthermore, the study revealed LncSICRNT1 modulated Beclin-1 ubiquitination and restrained macrophage autophagy by targeting TRAF6 expression. CONCLUSION: The study highlights XYT's potential to ameliorate LPS-induced SIMD by elevating LncSICRNT1 expression, influencing TRAF6 expression, and regulating Beclin-1 ubiquitination. These actions collectively inhibit macrophage autophagy and foster M1/M2 polarization, contributing to cardiac function improvement.

Omega-3 Lipid Mediators: Modulation of the M1/M2 Macrophage Phenotype and Its Protective Role in Chronic Liver Diseases.

The complex interplay between dietary factors, inflammation, and macrophage polarization is pivotal in the pathogenesis and progression of chronic liver diseases (CLDs). Omega-3 fatty acids (FAs) have brought in attention due to their potential to modulate inflammation and exert protective effects in various pathological conditions. Omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have shown promise in mitigating inflammation and enhancing the resolution of inflammatory responses. They influence the M1/M2 macrophage phenotype balance, promoting a shift towards the M2 anti-inflammatory phenotype. Specialized pro-resolving mediators (SPMs), such as resolvins (Rvs), protectins (PDs), and maresins (MaRs), have emerged as potent regulators of inflammation and macrophage polarization. They show anti-inflammatory and pro-resolving properties, by modulating the expression of cytokines, facilitate the phagocytosis of apoptotic cells, and promote tissue repair. MaR1, in particular, has demonstrated significant hepatoprotective effects by promoting M2 macrophage polarization, reducing oxidative stress, and inhibiting key inflammatory pathways such as NF-κB. In the context of CLDs, such as nonalcoholic fatty liver disease (NAFLD) and cirrhosis, omega-3s and their SPMs have shown promise in attenuating liver injury, promoting tissue regeneration, and modulating macrophage phenotypes. The aim of this article was to analyze the emerging role of omega-3 FAs and their SPMs in the context of macrophage polarization, with special interest in the mechanisms underlying their effects and their interactions with other cell types within the liver microenvironment, focused on CLDs and the development of novel therapeutic strategies.

Regulation of oxygen-glucose deprivation/reperfusion-induced inflammatory responses and M1-M2 phenotype switch of BV2 microglia by lobetyolin.

To elucidate the protective mechanism of lobetyolin on oxygen-glucose deprivation/reperfusion (OGD/R)-induced damage in BV2 microglial cells. The OGD/R model was established using a chemical modeling method to simulate in vivo brain ischemia in lobetyolin-pretreated BV2 cells. The optimum lobetyolin dosage, chemical concentration, and OGD/R modeling duration were screened. The changes in cell morphology were observed, and the levels of immune response-related factors, including tumor necrosis factor-α (TNF-α), interleukin-6, inducible nitric oxide synthase (iNOS), and cluster of differentiation (CD)206, were detected using the enzyme-linked immunosorbent assay. The expression of chemokine-like-factor-1 (CKLF1), hypoxia-inducible factor (HIF)-1α, TNF-α, and CD206, was detected using western blotting. The gene expression of M1 and M2 BV2 phenotype markers was assessed using quantitative polymerase chain reaction (qPCR). The localization of M1 and M2 BV2 markers was detected using immunofluorescence analysis. The results showed that lobetyolin could protect BV2 cells from OGD/R-induced damage. After OGD/R, CKLF1/C-C chemokine receptor type 4 (CCR4) levels increased in BV2 cells, whereas the CKLF1/CCR4 level was decreased due to lobetyolin pretreatment. Additionally, BV2 cells injured with OGD/R tended to be M1 type, but lobetyolin treatment shifted the phenotype of BV2 cells from M1 type to M2 type. Lobetyolin decreased the expression of TNF-α and HIF-1α but increased the expression of transforming growth factor-ß (TGF-ß) in BV2 cells, indicating a dose-effect relationship. The qPCR results showed that lobetyolin decreased the expression of CD16, CD32, and iNOS at the gene level and increased the expression of C-C-chemokine ligand-22 and TGF-ß. The immunofluorescence analysis showed that lobetyolin decreased CD16/CD32 levels and increased CD206 levels. Lobetyolin can protect BV2 cells from OGD/R-induced damage by regulating the phenotypic polarization of BV2 and decreasing inflammatory responses. Additionally, CKLF1/CCR4 may participate in regulating lobetyolin-induced polarization of BV2 cells via the HIF-1α pathway.

[Herbal cake-partitioned moxibustion regulates M1 and M2 macrophage polarization of colonic mucosa in rats with Crohn's disease].

OBJECTIVE: To observe the effect of herbal cake-partitioned moxibustion (Moxi) on the expressions of inflammatory factors and M1/M2 polarization in colonic mucosal macrophages in Crohn's disease (CD) rats, so as to explore its underlying mechanisms in the treatment of CD. METHODS: Forty male SD rats were randomly divided into normal, model, Moxi and medication groups (n=10). The CD model was established by enema of 2, 4, 6-trinitrobenzene sulfonic acid (TNBS) solution (5%TNBS∶50% alcohol=2∶1, 3 mL/kg), once every 7 days, 4 times altogether. For rats of the Moxi group, cake-partitioned moxibustion was given to "Tianshu" (ST25) and "Qihai" (CV6), two moxa-cones for each acupoint every time, once daily for 10 days. For rats of the medication group, intragastric perfusion of mesalazine solution was given twice daily for 10 days. After the treatment, the colonic mucosa tissue was sampled, and the macrophages were isolated, purified and cultured. The pathological changes of colon tissues were observed by H.E. staining. The ultrastructure of colon tissue was observed by transmission electron microscopy. The expression levels of α7nAChR, NF-κB p65 and TNF-α in colon mucosal macrophages were detected by Western blot. The number of M1 and M2 macrophages in colon mucosa was detected by flow cytometry and immunofluorescence assay. RESULTS: Compared with the normal group, the colon tissue of rats presented huge ulceration and inflammatory manifestations, the junction of colon epithelial cells was loose, the structure of organelles was damaged; the expression level of α7nAChR in macrophages of colon mucosa was significantly decreased (P<0.01), while the expression levels of NF-κB p65 and TNF-α, and the number of M1 and M2 macrophages were increased (P<0.01, P<0.05) in the model group. In comparison with the model group, the morphology and structure of colon mucosa tissues of rats in Moxi and medication groups were improved; the expression level of α7nAChR, the number of M2 macrophage in colon mucosa were significantly increased (P<0.01, P<0.05), while the expression levels of NF-κB p65 and TNF-α, and the number of M1 macrophage were significantly decreased (P<0.01, P<0.05) in both the Moxi and medication groups. CONCLUSION: Herbal cake-partitioned moxibustion may inhibit NF-κB activation by up-regulating the expression level of α7nAChR to promote the polarization of macrophages from M1 to M2 type, and reduce the proportion of M1 macrophages, inhibit the expression of TNF-α in colonic mucosa of CD rats, so as to relieve the intestinal inflammation.

Chitinase 3 like 1 deficiency ameliorates lipopolysaccharide-induced acute liver injury by inhibition of M2 macrophage polarization.

Chitinase 3-like-1 protein (CHI3L1) is involved in various infectious diseases, especially sepsis. Aberrant CHI3L1 expression potentially plays a critical role in chronic inflammation because a considerable number of macrophages are associated with immune/inflammatory diseases. In this study, we examined the effect of CHI3L1 on hepatic sepsis injury using a lipopolysaccharide (LPS)-induced model. LPS-treated CHI3L1 knockout (KO) mice exhibited a higher survival rate than LPS-treated CHI3L1 wild-type (WT) mice. In addition, hepatic injury-related enzyme levels (aspartate transaminase, alanine transaminase, and lactate dehydrogenase) decreased in CHI3L1 KO mice sera, suggesting attenuated LPS-induced septic liver damage in CHI3L1 KO mice. A greater reduction in the mRNA and protein expressions of M2 polarization markers, such as MRC1, ARG1, IL-10, and IL-4, was observed in LPS-induced CHI3L1 KO mice livers than in LPS-induced WT mice livers. Nonetheless, no change in the mRNA and protein expressions of M1 polarization markers, such as INOS, CD86, TNF-α, and IL6, was noted in LPS-induced CHI3L1 KO mice livers compared with those in LPS-induced WT and KO mice. Similar to the in vivo scenario, liver CHI3L1 depletion in LPS-treated HEP3B cells significantly decreased M2 polarization marker protein expression. However, M1 polarization marker protein expression did not differ significantly. These results suggest that CHI3L1 depletion decreases M2 macrophage polarization, and this effect is potentially associated with the alleviation of liver sepsis in CHI3L1 KO mice.

Licochalcone E, a ß-Amyloid Aggregation Inhibitor, Regulates Microglial M1/M2 Polarization via Inhibition of CTL1-Mediated Choline Uptake.

Alzheimer's disease (AD) is thought to be a series of neuroinflammatory diseases caused by abnormal deposits of amyloid-ß (Aß) and tau protein in the brain as part of its etiology. We focused on Aß aggregation and M1 and M2 microglial polarity in microglia to search for novel therapeutic agents. It has been reported that the inhibition of choline uptake via choline transporter-like protein 1 (CTL1) in microglia preferentially induces M2 microglial polarity. However, the role of the choline transport system on the regulation of microglial M1/M2 polarity in AD is not fully understood. Licochalcones (Licos) A-E, flavonoids extracted from licorice, have been reported to have immunological anti-inflammatory effects, and Lico A inhibits Aß aggregation. In this study, we compared the efficacy of five Licos, from Lico A to E, at inhibiting Aß1-42 aggregation. Among the five Licos, Lico E was selected to investigate the relationship between the inhibition of choline uptake and microglial M1/M2 polarization using the immortalized mouse microglial cell line SIM-A9. We newly found that Lico E inhibited choline uptake and Aß1-42 aggregation in SIM-A9 cells in a concentration-dependent manner, suggesting that the inhibitory effect of Lico E on choline uptake is mediated by CTL1. The mRNA expression of tumor necrosis factor (TNF-α), a marker of M1 microglia, was increased by Aß1-42, and its effect was inhibited by choline deprivation and Lico E in a concentration-dependent manner. In contrast, the mRNA expression of arginase-1 (Arg-1), a marker of M2 microglia, was increased by IL-4, and its effect was enhanced by choline deprivation and Lico E. We found that Lico E has an inhibitory effect on Aß aggregation and promotes polarity from M1 to M2 microglia via inhibition of the CTL1 function in microglia. Thus, Lico E may become a leading compound for a novel treatment of AD.

Macrophage efferocytosis in health and disease.

Creating cellular homeostasis within a defined tissue typically relates to the processes of apoptosis and efferocytosis. A great example here is cell debris that must be removed to prevent unwanted inflammatory responses and then reduce autoimmunity. In view of that, defective efferocytosis is often assumed to be responsible for the improper clearance of apoptotic cells (ACs). This predicament triggers off inflammation and even results in disease development. Any disruption of phagocytic receptors, molecules as bridging groups, or signaling routes can also inhibit macrophage efferocytosis and lead to the impaired clearance of the apoptotic body. In this line, macrophages as professional phagocytic cells take the lead in the efferocytosis process. As well, insufficiency in macrophage efferocytosis facilitates the spread of a wide variety of diseases, including neurodegenerative diseases, kidney problems, types of cancer, asthma, and the like. Establishing the functions of macrophages in this respect can be thus useful in the treatment of many diseases. Against this background, this review aimed to recapitulate the knowledge about the mechanisms related to macrophage polarization under physiological or pathological conditions, and shed light on its interaction with efferocytosis.

Conditioned medium from bone marrow mesenchymal stem cells relieves spinal cord injury through suppression of Gal-3/NLRP3 and M1 microglia/macrophage polarization.

The therapeutic effects of bone marrow mesenchymal stem cells (BMSCs) and their conditioned media have been well-documented. This study focused on the effects of BMSC-conditioned medium (BMSCcm) on spinal cord injury (SCI). To study the effects of BMSCcm on rat motor function, inflammatory response, and M1/M2 macrophage/microglial polarization, SCI model rats were treated with BMSCcm and vectors for overexpression of galectin-3 (Gal-3) or NLR family pyrin domain containing 3 (NLRP3). Treatment with BMSCcm reduced the expression of Gal-3 and NLRP3, alleviated the inflammatory response, suppressed M1 microglia/macrophage polarization, and triggered M2 microglia/macrophage polarization in SCI model rats. Meanwhile, overexpression of Gal-3 or NLRP3 counteracted the suppressive effect of BMSCcm on SCI. Moreover, during BMSCcm treatment, overexpression of Gal-3 promoted the expression of NLRP3, whereas overexpression of NLRP3 had no significant effect on the expression of Gal-3. Additionally, the effects of BMSCcm on macrophage/microglial polarization and the underlying molecular mechanisms were observed in vitro. This study demonstrated that BMSCcm alleviates SCI by suppressing the expression of Gal-3 and NLRP3.

New Insights into Baicalein's Effect on Chlorpyrifos-Induced Liver Injury in Carp: Involving Macrophage Polarization and Pyropto sis.

Chlorpyrifos (CPF) is widely used in agriculture, plants, and buildings to kill pests and worms. Excessive environmental residues of CPF will result in soil and ecological contamination and toxicity to animals and humans. Baicalein (Bai), derived from the root of natural Scutellaria baicalensis, is a potent anti-inflammatory, antioxidant, and antitumor agent. The objective of this paper is to investigate the molecular mechanism by which Bai prevents CPF-induced hepatotoxic injury. Carp were kept in water containing CPF (23.2 µg/L) and/or fed diets containing Bai (0.15 g/kg). We found that Bai attenuated liver tissue damage and vacuolization caused by CPF. We confirmed that CPF causes M1/M2 polarization imbalance in macrophages and hepatocyte pyroptosis, which ultimately leads to liver injury. Further exploration of the internal mechanism shows that CPF participates in liver toxicity damage by destroying the AMPK/SIRT1/pGC-1α pathway and causing mitochondrial biogenesis and mitochondrial dynamics imbalance. Notably, Bai significantly attenuated CPF-induced inhibition of the AMPK/SIRT1/pGC-1α pathway. In summary, our results suggest that Bai alleviates CPF exposure-induced inhibition of the AMPK/SIRT1/pGC-1α pathway, thereby attenuating macrophage M1 hyperpolarization and pyroptosis by inhibiting the NF-κB pathway. These results may provide new insights into the detoxification mechanism of Bai on the same type of organophosphorus pesticides.