Phagocytic Ability Research Articles

Vitamin C suppresses toxicological effects in MO/MФ and IgM+ B cells of Nile tilapia (Oreochromis niloticus) upon copper exposure.

Copper (Cu), as an essential micronutrient in human and animal metabolism, easily spreads and excessively accumulates in rearing water, which make it more susceptible to fish farms and threatens the health of aquatic animals. In this issue, the protective effect of vitamin C against oxidative damage caused by copper exposure was studied in monocytes/macrophages (MO/MФ) and IgM+ B cells of Nile tilapia (Oreochromis niloticus), the cell types possessing phagocytic activities. The significant increase of ROS level and up-regulation of proinflammatory factors accompanied by depletion of GSH and down-regulation of antioxidative molecules in MO/MФ and IgM+ B cells, when stressed with CuO NPs or Cu ions, indicated the induction of oxidative damage due to the toxicological effects with copper exposure. Copper induced cell apoptosis through mitochondrial-dependent pathway in these two cell populations was demonstrated with disruption of mitochondrial membrane potential (ΔΨm) and activation of apoptosis factor. Furthermore, the phagocytic abilities for microspheres and bioparticle uptake significantly decreased in these two cell populations upon CuO NPs or Cu ions; meanwhile, antigen presentation of MO/MФ and antibody production of IgM+ B cells were also inhibited. However, vitamin C supplementation reversed all these biochemical indices, as well as cell apoptosis and phagocytic abilities in MO/MФ and IgM+ B cells that were induced by CuO NPs or Cu ions. In conclusion, these results revealed that vitamin C exerts cytoprotective effects against oxidative damage through its antioxidant properties and may be of therapeutic use in preventing toxicological effects caused by copper exposure.

A specific primed immune response in red palm weevil, Rhynchophorus ferrugineus, is mediated by hemocyte differentiation and phagocytosis

Red palm weevil, Rhynchophorus ferrugineus, is an invasive and destructive pest that causes serious damages to palm trees. Like other invertebrates, red palm weevil relies solely on its innate immune response to fight invading microbes; by definition, innate immunity lacks adaptive characteristics. However, we show here that priming the red palm weevil larvae with heat-killed Bacillus thuringiensis specifically increased survival of the larvae during a secondary lethal infection with live bacteria, and B. thuringiensis primed larvae also showed a higher clearance efficiency for this bacterium, which indicated that the red palm weevil larvae possessed a strong immune priming response. The degree of enhanced immune protection was positively correlated with hemocyte proliferation and the level of phagocytic ability of hemocytes. Moreover, the red palm weevil larvae primed by B. thuringiensis induced the continuous synthesis of serotonin in the hemolymph, which in turn enhanced the phagocytic ability and pathogen clearance ability of the host, representing an important mechanism for the red palm weevil to achieve priming protection. Our findings reveal a specific immune priming of the red palm weevil larvae mediated by the continuous secretion of serotonin, and provide new insights into the mechanisms of invertebrates immune priming.

Magnetically Actuated Cell-Robot System: Precise Control, Manipulation, and Multimode Conversion.

Border-nearing microrobots with self-propelling and navigating capabilities have promising applications in micromanipulation and bioengineering, because they can stimulate the surrounding fluid flow for object transportation. However, ensuring the biosafety of microrobots is a concurrent challenge in bioengineering applications. Here, macrophage template-based microrobots (cell robots) that can be controlled individually or in chain-like swarms are proposed, which can transport various objects. The cell robots are constructed using the phagocytic ability of macrophages to load nanomagnetic particles while maintaining their viability. The robots exhibit high position control accuracy and generate a flow field that can be used to transport microspheres and sperm when exposed to an external magnetic field near a wall. The cell robots can also form chain-like swarms to transport a large object (more than 100 times the volume). This new insight into the manipulation of macrophage-based cell robots provides a new concept by converting other biological cells into microrobots for micromanipulation in biomedical applications.

Toxicological damages on copper exposure to IgM+ B cells of Nile tilapia (Oreochromis niloticus) and mitigation of its adverse effects by β-glucan administration

Present investigation was carried out to study toxicological damages of copper exposure and mitigation of its adverse effects with β-glucan administration in IgM+ B cells which processes multiple roles similar to macrophages in Nile tilapia (Oreochromis niloticus). IgM+ B cells were pretreated with β-glucan (25 μg/mL) for 24 h before exposed to cupric oxide nanoparticles (CuO NPs) or cupric chloride (Cu ions) at the doses of 0, 5, 10, and 20 μg/mL for 24 h, respectively. Our results demonstrated that β-glucan increased reduced glutathione (GSH) to against oxidative damage from CuO NPs and Cu ions exposure in IgM+ B cells. The apoptosis process through mitochondrial signaling pathway was depressed in IgM+ B cells since the mitochondrial membrane potential (ΔΨm) was protected from copper exposure by β-glucan treatment. Furthermore, the inhibition on phagocytic abilities of IgM+ B cells caused by copper exposure could be enhanced with β-glucan treatment via evaluation of microspheres and bioparticles uptake and LPS-induced NO production. Importantly, β-glucan might participate in immunomodulation in IgM+ B cells through B cell antigen receptor (BCR) to suppress toxicological effect derived from copper exposure. Taken together, this study provides more information on the toxicological damages in IgM+ B cells upon copper exposure and explains the molecular mechanism to reverse adverse effects caused by copper exposure with β-glucan administration.

Separation and phagocytosis analysis of peripheral blood leukocytes from Qihe crucian carp Carassius auratus

The phagocytic function of peripheral blood leukocytes (PBL) in teleost fish is the bridge between cellular-mediated and humoral immunity and plays a central role in the immune system of the teleost fish. However, the phagocytic ability of PBL from Qihe crucian carp Carassius auratus remains unclear. This study aimed to build a convenient separation method to obtain high purity PBL from Qihe crucian carp and to explore their phagocytic characteristics. The results showed that the PBL of Qihe crucian carp (QPBL) could be obtained effectively by 1.085 g/ml percoll separation liquid. Most isolated QPBL were round or elliptical, with horseshoe-shaped, reniform, or irregular nucleus. Finger-like or filamentous protrusions were present on the cell surface, and some cells had a long pseudopod. According to the results of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and fluorescence microscope, fluoresbrite carboxylate YG microspheres (1 μm) could be effectively phagocytosed by QPBL, and various phagocytic stages could be observed. The phagocytic cells in QPBL have morphology similar to those of “professional” phagocytes (monocyte and granulocyte). Notably, the percentage of cells, which can engulf microspheres, increased to approximately 22% after incubation with microspheres for 90 min, and it showed no obvious changes until 180 min. Furthermore, two important phagocytosis regulatory protein genes, Rab5 and Rab7, were seriously up-regulated during the phagocytosis in QPBL. Taken together, an efficient and convenient separation method for isolating QPBL was established, and the isolated QPBL had a high phagocytic activity towards the external particles. The results could provide the basic foundation for further study of the immune function of PBL in Qihe crucian carp and other teleost fish.

CAR-macrophage: An extensive immune enhancer to fight cancer.

CAR-macrophage: An extensive immune enhancer to fight cancer.

Mapping the Plasticity of Morphology, Molecular Properties and Function in Mouse Primary Microglia.

Microglia exert diverse functions by responding in diverse ways to different stimuli, yet little is known about the plasticity of various phenotypes that microglia display. We used interferon (IFN)-γ, interleukin (IL)-4 and IL-10 to induce different phenotypes in mouse primary microglia. RNA sequencing was used to identify genes differentially expressed in response to stimulation, and the different stimulated populations were compared in terms of morphology, proliferative capacity, phagocytic ability and neurotoxicity. IFN-γ induced an “immunodefensive” phenotype characterizing both induction of filopodia and upregulation of inducible nitric oxide synthase (iNOS) and tumor necrosis factor α. Microglia with this phenotype mediated an acute inflammatory response accompanied by excellent proliferative capacity and neurotoxicity, and remained susceptible to remodeling for up to 48 h after initial stimulation. IL-4 induced an enduring “neuroimmunoregulatory” phenotype involving induction of lamellipodium and persistent upregulation of arginase (Arg)-1 and YM-1 expression. Microglia with this phenotype remained susceptible to remodeling for up to 24 h after initial stimulation. IL-10 induced an “immunosuppressive” phenotype involving induction of ameba-like morphology and upregulation of transforming growth factor β and IL-10 as well as inhibition of inflammation. This phenotype was accompanied by inhibition of self-proliferation, while its morphology, molecular properties and function were the least susceptible to remodeling. IFN-γ, IL-4, or IL-10 appear to induce substantially different phenotypes in microglia. The immunodefensive microglia induced by IFN-γ showed remarkable plasticity, which may help repair CNS inflammation damage under pathological condition. Chronic activation with IL-10 decreases microglial plasticity, which may help protect the brain form the immune response. Our research justifies and guides further studies into the molecular pathways that operate in each phenotype to help multitasking microglia regulate homeostasis in the brain.

Immunomodulatory effects of the polysaccharide from Sinonovacula constricta on RAW264.7 macrophage cells.

This study aimed to evaluate the immunomodulatory effect of the polysaccharide from Sinonovacula constricta (SCP‐1‐1) in RAW264.7 cells. SCP‐1‐1 with a molecular weight of 440.0 kDa consisted of glucose and mannose. The immunomodulatory assay results showed that SCP‐1‐1 could significantly enhance phagocytic ability, NO production, and some cytokines (TNF‐α, IL‐6, and IL‐1β) secretion of RAW264.7 cell in a dose‐dependent manner. Western blot analysis results demonstrated that SCP‐1‐1 could regulate the expression levels of the key proteins in the signaling pathways of RAW264.7 cell and might associated with NF‐κβ and PI3K signaling pathway. These findings could contribute to elucidate the immunomodulatory activities of the polysaccharide from Sinonovacula constricta.

Particle uptake driven phagocytosis in macrophages and neutrophils enhances bacterial clearance

Humans are exposed to numerous synthetic foreign particles in the form of drug delivery systems and diagnostic agents. Specialized immune cells (phagocytes) clear these particles by phagocytosing and attempting to degrade them. The process of recognition and internalization of the particles may trigger changes in the function of phagocytes. Some of these changes, especially the ability of a particle-loaded phagocyte to take up and neutralize pathogens, remains poorly studied. Herein, we demonstrate that the uptake of non-stimulatory cargo-free particles enhances the phagocytic ability of monocytes, macrophages and neutrophils. The enhancement in phagocytic ability was independent of particle properties, such as size or the base material constituting the particle. Additionally, we show that the increased phagocytosis was not a result of cellular activation or cellular heterogeneity but was driven by changes in cell membrane fluidity and cellular compliance. A consequence of the enhanced phagocytic activity was that particulate-laden immune cells neutralize Escherichia coli (E. coli) faster in culture. Moreover, when administered in mice as a prophylactic, particulates enable faster clearance of E. coli and Staphylococcus epidermidis. Together, we demonstrate that the process of uptake induces cellular changes that favor additional phagocytic events. This study provides insights into using non-stimulatory cargo-free particles to engineer immune cell functions for applications involving faster clearance of phagocytosable abiotic and biotic material.

Endogenous expression of Notch pathway molecules in human trabecular meshwork cells

PurposeCells in the trabecular meshwork sense and respond to a myriad of physical forces through a process known as mechanotransduction. Whilst the effect of substratum stiffness or stretch on TM cells have been investigated in the context of transforming growth factor (TGF-β), Wnt and YAP/TAZ pathways, the role of Notch signaling, an evolutionarily conserved pathway, recently implicated in mechanotransduction, has not been investigated in trabecular meshwork (TM) cells. Here, we compare the endogenous expression of Notch pathway molecules in TM cells from glaucomatous and non-glaucomatous donors, segmental flow regions, and when subjected to cyclical strain, or grown on hydrogels of varying rigidity. MethodsPrimary TM from glaucomatous (GTM), non-glaucomatous (NTM) donors, and from segmental flow regions [high flow (HF), low flow (LF)], were utilized between passages 2–6. Cells were (i) plated on tissue culture plastic, (ii) subjected to cyclical strain (6 h and 24 h), or (iii) cultured on 3 kPa and 80 kPa hydrogels. mRNA levels of Notch receptors/ligands/effectors in the TM cells was determined by qRT-PCR. Phagocytosis was determined as a function of substratum stiffness in NTM-HF/LF cells in the presence or absence of 100 nM Dexamethasone treatment. ResultsInnate expression of Notch pathway genes were significantly overexpressed in GTM cells with no discernible differences observed between HF/LF cells in either NTM or GTM cells cultured on plastic substrates. With 6 h of cyclical strain, a subset of Notch pathway genes presented with altered expression. Expression of Notch receptors/ligands/receptors/inhibitors progressively declined with increasing stiffness and this correlated with phagocytic ability of NTM cells. Dexamethasone treatment decreased phagocytosis regardless of stiffness or cells isolated from segmental outflow regions. ConclusionsWe demonstrate here that the Notch expression in cultured TM cells differ intrinsically between GTM vs NTM, and by substratum cues (cyclical strain and stiffness). Of import, the most apparent differences in gene expression were observed as a function of substratum stiffness which closely followed phagocytic ability of cells. Interestingly, on soft substrates (mimicking normal TM stiffness) Notch expression and phagocytosis was highest, while both expression and phagocytosis was significantly lower on stiffer substrates (mimicking glaucomatous stiffness) regardless of DEX treatment. Such context dependent changes suggest Notch pathway may play differing roles in disease vs homeostasis. Studies focused on understanding the mechanistic role of Notch (if any) in outflow homeostasis are thus warranted.

MicroRNA-181c-5p modulates phagocytosis efficiency in bone marrow-derived macrophages.

Phagocytosis and clearance of apoptotic cells are essential for inflammation resolution, efficient wound healing, and tissue homeostasis. MicroRNAs are critical modulators of macrophage polarization and function. The current study aimed to investigate the role of miR-181c-5p in macrophage phagocytosis. miR-181c-5p was identified as a potential candidate in microRNA screening of RAW264.7 macrophages fed with apoptotic cells. To investigate the role of miR-181c-5p in phagocytosis, the expression of miR-181c-5p was assessed in phagocyting bone marrow-derived macrophages. Phagocytosis efficiency was measured by fluorescence microscopy. Gain- and loss-of-function studies were performed using miR-181c-5p-specific mimic and inhibitor. The expression of the phagocytosis-associated genes and proteins of interest was evaluated by RT2 profiler PCR array and western blotting, respectively. miR-181c-5p expression was significantly upregulated in the phagocyting macrophages. Furthermore, mimic-induced overexpression of miR-181c-5p resulted in the increased phagocytic ability of macrophages. Moreover, overexpression of miR-181c-5p resulted in upregulation of WAVE-2 in phagocyting macrophages, suggesting that miR-181c-5p may regulate cytoskeletal arrangement during macrophage phagocytosis. Altogether, our data provide a novel function of miR-181c-5p in macrophage biology and suggest that targeting macrophage miR-181c-5p in injured tissues might improve clearance of dead cells and lead to efficient inflammation resolution.

Structure elucidation and immunological activity of a novel exopolysaccharide from Paenibacillus bovis sp. nov BD3526

A novel exopolysaccharide named BD0.4 was purified from the fermentation broth of Paenibacillus bovis sp. nov BD3526 in wheat bran medium via anion exchange column chromatography. Its fine structure was identified by a variety of physical and chemical methods. BD0.4, with the weight average molecular weight of 376 kDa, consisted of glucuronic acid, glucose and fucose in a molar ratio of 1.58:1:1.66. The backbone included 1,3-linked Fuc, 1,3,4-linked Fuc, 1,3-linked Glc and 1,4-linked GlcA residues, with the branching point located at the O4 position of 1,3,4-linked Fuc residues, and the branched chain composed of terminal GlcA residues. BD0.4 could improve the phagocytic ability of macrophages and significantly stimulate the secretion of NO, TNF-α, IL-1β and IL-6 from RAW264.7 cells in a dose-dependent manner. BD0.4 could promote the expression of NF-кB and cause nuclear translocation of NF-κB p65, indicating that BD0.4 probably exerted immune activity through the NF-κB signaling pathway.

Resolvin D2 promotes host defense in a 2 - hit model of sepsis with secondary lung infection

In the development of sepsis, there is early, massive inflammation which can lead to multiple organ failure. Later there is an immunosuppressed phase where the host is susceptible to secondary infections or is unable to clear existing infection. Specialized Pro-resolving Mediators (SPMs) are endogenously produced lipids which resolve infection by decreasing bacteria load and reducing systemic inflammatory response. There has been little work studying if SPMs given late, can promote host defense. We examined if an SPM, Resolvin D2 (RvD2) could promote host defense in a 2-hit mouse model of cecal ligation and puncture (CLP) sepsis and secondary Pseudomonas aeruginosa lung infection. RvD2 given 48 h after mild CLP (1st hit), increased gene expression of Toll-like receptor-2 (TLR-2) and alveolar macrophage/monocyte phagocytic ability compared to CLP mice given saline vehicle. In this model, RvD2 did not affect plasma IL-6 or IL-10. These effects induced by RvD2, lowered lung bacterial load and decreased mortality after the secondary infection of Pseudomonas aeruginosa (2nd hit). Splenic T-cell numbers were also increased in RvD2 treated mice compared to saline vehicle treated animals. The results suggest that RvD2 promoted mechanisms of host defense in a 2-hit model sepsis and secondary lung infection.

β-glucan mitigation on toxicological effects in monocytes/macrophages of Nile tilapia (Oreochromis niloticus) following copper exposure

The protective effect of β-glucan against toxicological effects caused by copper oxide nanoparticles (Cu NPs) and copper ions (Cu ions) were studied in monocytes/macrophages (MO/MФ) of Nile tilapia (Oreochromis niloticus). Our results demonstrated that CuO NPs and Cu ions exposure aroused strong oxidative lesion in MO/MФ by detection of cellular reactive oxygen species (ROS) and reduced glutathione (GSH), as well as identification of several antioxidant-related cytokines. Meanwhile, the serious pro-inflammatory responses were accompanied during the processes of oxidative lesion by TNFα, IL-1β, and IL-6 genes validation. Copper induced MO/MФ underwent apoptosis through mitochondrial signaling pathway by mitochondrial membrane potential (ΔΨm) detection and Bax, Bcl-2, Cyt-c, Apaf-1, Caspase 9, Caspase 3 genes validation. Furthermore, the phagocytic abilities were inhibition in MO/MФ by evaluation of microspheres (0.5 and 1.0 μm beads) and bioparticles (S. agalactiae and A. hydrophila) uptake and LPS-induced NO production. However, β-glucan might participate in immunomodulation through C-type lectin receptor (CLR) and complement receptor 3 (CR3) to suppress pro-inflammatory responses, thereby revered all the copper induced aforementioned adverse effects in MO/MΦ. Taken together, our results provide insights on the mechanisms through β-glucan administration to mitigate toxicological effects of CuO NPs and Cu ions exposure to the MO/MΦ, which will benefit aspects related to fish farming and aquaculture production.

Comparative studies on the structure, biological activity and molecular mechanisms of polysaccharides from Craterellus cornucopioide (CC-M) and Dictyophora indusiata (Vent.ex Pers) Fisch (DI-Z)

In this study, two new polysaccharides were extracted from the fruiting bodies of Craterellus cornucopioide and Dictyophora indusiata (Vent.ex Pers) Fisch, respectively. The results showed that CC-M was composed of Xyl: Glc: Gal in a ratio of 2:5:4. The CC-M takes 1,6-glucose and 1,6-galactose as skeletons, extends a branched chain from galactose 2-O to connect 1,3,4-xylose, and connects β-4-glucose terminal monosaccharide to xylose. DI-Z was also composed of Xyl: Glc: Gal in the ratio of 2:6:5, which takes 1,6-glucose and 1,6-galactose as skeletons, extends a branched chain from galactose 2-O to connect 1,4-xylose and β-4-glucose as terminal group. The results of immunoactivity showed that CC-M and DI-Z have the proliferation activity of B cells, T cells and RAW264.7 cells in vitro, and the effect of CC-M on the proliferation of immune cells was higher than that of DI-Z. In addition, CC-M could significantly promote the secretion of TNF - α, IL-6, IL-1 β, IL-10 and CD163 and enhance the phagocytic ability of RAW264.7 cells. The results of RNA-sequencing showed that CC-M exerted its proliferative activity and immunoregulatory activity on RAW264.7 cells through the interaction of MAPK signaling pathway, NOD like receptor signaling pathway, PI3K-Akt signaling pathway and NF-κB signaling pathway.

Immunomodulatory effects of Blaps rynchopetera extract.

ABSTRACTPurpose:To explore the potential immunomodulatory effects of total extract and different polar parts from Blaps rynchopetera Fairmaire.Methods:Phagocytic activity was evaluated by neutral red assay, and the effect of the immune function was investigated by normal and immunocompromised mice models.Results: In vitro, total extract, as well as chloroform, ethyl acetate, n-butanol and water fractions could individually enhance the phagocytic ability of mouse peritoneal macrophages; in addition, chloroform and ethyl acetate fractions had an increasing tendency when combined stimulation with lipopolysaccharide (LPS). In vivo, ethyl acetate fraction (EAF) could enhance the immune organ index, increase the serum hemolysin level and peripheral blood immune cells of immunocompromised mice, while for normal mice, the effect was inconspicuous.Conclusions: Blaps rynchopetera extracts had noteworthy immunomodulatory effect, especially for individuals with immune disorders.

Exosomes derived from olfactory ensheathing cells provided neuroprotection for spinal cord injury by switching the phenotype of macrophages/microglia.

Transplantation of olfactory ensheathing cells (OECs) has been demonstrated to be beneficial for spinal cord injury (SCI) by modulating neuroinflammation, supporting neuronal survival and promoting angiogenesis. Besides OECs, the conditioned medium (CM) from OECs has also been proved to have therapeutic effects for SCI, indicating that the bioactive substances secreted by OECs are essential for its protective effects. Nevertheless, there is still little information regarding the underlying mechanisms. Considering that exosomes are crucial for intercellular communication and could be secreted by different types of cells, we speculated that the therapeutic potential of OECs for SCI might be partially based on their exosomes. To examine whether OECs could secret exosomes, we isolated exosomes by polyethylene glycol‐based method, and identified them by electron microscopy study, nanoparticle tracking analysis (NTA) and western blotting. In view of phagocytic ability of microglia and its distinct roles in microenvironment regulation after SCI, we then focused the effects of OECs‐derived exosomes (OECs‐Exo) on microglial phenotypic regulation. We found that the extracted OECs‐Exo could be engulfed by microglia and partially reverse the LPS‐induced pro‐inflammatory polarization through inhibiting NF‐κB and c‐Jun signaling pathways in vitro. Furthermore, OECs‐Exo were found to inhibit the polarization of pro‐inflammatory macrophages/microglia while increased the numbers of anti‐inflammatory cells after SCI. Considering that the neuronal injury is closely related to the activation state of macrophages/microglia, co‐culture of microglia and neurons were performed. Neuronal death induced by LPS‐treated microglia could be significantly alleviated when microglia treated by LPS plus OECs‐Exo in vitro. After SCI, NeuN‐immunostaining and axonal tract‐tracing were performed to assess neuronal survival and axon preservation. Our data showed that the OECs‐Exo promoted the neuronal survival and axon preservation, and facilitated functional recovery after SCI. Our findings provide a promising therapeutic strategy for SCI based on exosome‐immunomodulation.

Insomnia and depressive behavior of MyD88-deficient mice: Relationships with altered microglial functions

Myeloid differentiation primary response gene 88 (MyD88) is essential for microglial activation. Despite the significant role of microglia in regulating sleep homeostasis, the contribution of MyD88 to sleep is yet to be determined. To address this, we performed electroencephalographic and electromyographic recordings on MyD88-KO mice and wild-type mice to investigate their sleep/wake cycles. In the daytime, MyD88-KO mice exhibited prolonged wakefulness and shorter non-rapid eye movement sleep duration. Tail suspension and sucrose preference tests revealed that MyD88-KO mice displayed a depressive-like phenotype. We determined monoamines in the prefrontal cortex (PFC) using high-performance liquid chromatography and observed a decreased content of serotonin in the PFC of MyD88-KO mice. Flow cytometry revealed that CD11b, CD45, and F4/80 expressions were elevated at Zeitgeber time (ZT) 1 compared to at ZT13 only in wild-type mice. Furthermore, MFG-E8 and C1qB-tagged synapses were enhanced at ZT1 in the PFC of wild-type mice but not in MyD88-KO mice. Primary cultured microglia from MyD88-KO mice revealed decreased phagocytic ability. These findings indicate that genetic deletion of MyD88 induces insomnia and depressive behavior, at least in part, by affecting microglial homeostasis functions and lowering the serotonergic neuronal output.

Regulatory Effects of Quercetin on M1/M2 Macrophage Polarization and Oxidative/Antioxidative Balance.

Macrophage polarization plays essential and diverse roles in most diseases, such as atherosclerosis, adipose tissue inflammation, and insulin resistance. Homeostasis dysfunction in M1/M2 macrophage polarization causes pathological conditions and inflammation. Neuroinflammation is characterized by microglial activation and the concomitant production of pro-inflammatory cytokines, leading to numerous neurodegenerative diseases and psychiatric disorders. Decreased neuroinflammation can be obtained by using natural compounds, including flavonoids, which are known to ameliorate inflammatory responses. Among flavonoids, quercetin possesses multiple pharmacological applications and regulates several biological activities. In the present study, we found that quercetin effectively inhibited the expression of lipocalin-2 in both macrophages and microglial cells stimulated by lipopolysaccharides (LPS). The production of nitric oxide (NO) and expression levels of the pro-inflammatory cytokines, inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, were also attenuated by quercetin treatment. Our results also showed that quercetin significantly reduced the expression levels of the M1 markers, such as interleukin (IL)-6, tumor necrosis factor (TNF)-α, and IL-1β, in the macrophages and microglia. The M1 polarization-associated chemokines, C–C motif chemokine ligand (CCL)-2 and C-X-C motif chemokine ligand (CXCL)-10, were also effectively reduced by the quercetin treatment. In addition, quercetin markedly reduced the production of various reactive oxygen species (ROS) in the microglia. The microglial phagocytic ability induced by the LPS was also effectively reduced by the quercetin treatment. Importantly, the quercetin increased the expression levels of the M2 marker, IL-10, and the endogenous antioxidants, heme oxygenase (HO)-1, glutamate-cysteine ligase catalytic subunit (GCLC), glutamate-cysteine ligase modifier subunit (GCLM), and NAD(P)H quinone oxidoreductase-1 (NQO1). The enhancement of the M2 markers and endogenous antioxidants by quercetin was activated by the AMP-activated protein kinase (AMPK) and Akt signaling pathways. Together, our study reported that the quercetin inhibited the effects of M1 polarization, including neuroinflammatory responses, ROS production, and phagocytosis. Moreover, the quercetin enhanced the M2 macrophage polarization and endogenous antioxidant expression in both macrophages and microglia. Our findings provide valuable information that quercetin may act as a potential drug for the treatment of diseases related to inflammatory disorders in the central nervous system.

CCAAT/enhancer binding protein (C/EBP) delta promotes the expression of PTX3 and macrophage phagocytosis during A. fumigatus infection.

Given the increasing incidence of pulmonary aspergillosis, it is important to understand the natural defense mechanisms by which the body can kill Aspergillus fumigatus conidia. Pentraxin 3 (PTX3) plays a nonredundant role in resistance to A. fumigatus. Here, we found that the key predicted PTX3 transcription factor, CCAAT/enhancer-binding protein δ (CEBPD), was up-regulated during A. fumigatus conidia infection. Functionally, CEBPD significantly promoted the expression of PTX3 and the phagocytic ability of macrophages. Mechanistically, CEBPD activated the PTX3 by directly binding to the promoter region of the PTX3 gene. We also showed that the RNA-binding protein human antigen R promoted CEBPD expression. These findings provide new insights into the crucial role of CEBPD in the phagocytosis of A. fumigatus conidia by macrophages and highlight this protein as a potential therapeutic target for invasive pulmonary aspergillosis.