Macrophage activation by endogenous danger signals

BVDV Npro protein mediates the BVDV induced immunosuppression through interaction with cellular S100A9 protein

The innate immune response is a vital part of the body's antiviral defense system. The innate immune response is initiated by various receptor interactions, including danger associated molecular patterns (DAMPs). The S100A9 is a member of the DAMPs protein family and, is released by activated phagocytic cells such as neutrophils, monocytes, macrophages or endothelial cells, and S100A9 induces its effect through TLR4/MyD88 pathway.

Bovine viral diarrhea virus (BVDV) is one of the major devastating disease in the cattle industry worldwide. It shows its effect through immunosuppression and develops persistent infection in calves born from infected cows. The current study revealed that BVDV potentially induced immunosuppression by the interaction of BVDV Npro protein with cellular S100A9 protein. The Inhibition of S100A9 protein expression by small interfering RNA (siRNA) enhanced the virus replication in infected cells. Overexpression of bovine S100A9 enhanced the ncpBVDV2a 1373 mediated Type-I interferon production. A co-immunoprecipitation experiment demonstrated a strong interaction between ncp BVDV2a 1373 Npro protein and cellular S100A9 protein. This suggested that BVDV Npro reduced the S100A9 protein availability/activity in infected cells, resulting in reduced Type-I interferon production. A further study of S100A9-BVDV interaction will be need for better understanding of BVDV pathophysiology.

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The bovine viral diarrhea virus (BVDV) nonstructural protein, Npro, is responsible for immunosuppression.

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The mechanism of Npro immune immunosuppression is not well characterized.

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S100A9, a cell protein that contains danger associated molecular patterns (DAMP), is important in innate immunity.

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S100A9 protein and Npro protein associate while overexpression of S100A9 enhanced Type-I interferon production.

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Inhibition of S100A9 by siRNA aided BVDV replication. Npro interacting with S100A9 may result in immunosuppression.

Arctigenin Induces an Activation Response in Porcine Alveolar Macrophage Through TLR6-NOX2-MAPKs Signaling Pathway

Arctigenin (ARG), one of the most active ingredients abstracted from seeds of Arctium lappa L., has been proved to exert promising biological activities such as immunomodulatory, anti-viral, and anti-cancer etc. However, the mechanism behind its immunomodulatory function still remains elusive to be further investigated. In this study, we found that ARG had no significant effects on the cell proliferation in both porcine alveolar macrophage cell line (3D4/21) and primary porcine derived alveolar macrophage. It remarkably increased the expression and secretion of the two cytokines including tumor necrosis factor-alpha (TNF-α) and transforming growth factor beta1 (TGF-β1) in a dose-dependent manner with the concomitant enhancement of phagocytosis, which are the indicators of macrophage activation. ARG also elevated the intracellular reactive oxygen species (ROS) production by activating NOX2-based NADPH oxidase. Furthermore, inhibition of ROS generation by diphenyliodonium and apocynin significantly suppressed ARG-induced cytokine secretion and phagocytosis increase, indicating the requirement of ROS for the porcine alveolar macrophage activation. In addition, TLR6-My88 excitation, p38 MAPK and ERK1/2 phosphorylation were all involved in the process. As blocking TLR6 receptor dramatically attenuated the NOX2 oxidase activation, cytokine secretion and phagocytosis increase. Inhibiting ROS generation almost abolished p38 and ERK1/2 phosphorylation, and the cytokine secretion could also be remarkably reduced by p38 and ERK1/2 inhibitors (SB203580 and UO126). Our finding gave a new insight of understanding that ARG could improve the immune-function of porcine alveolar macrophages through TLR6-NOX2 oxidase-MAPKs signaling pathway.

Neutrophils Inhibit Synthesis of Mineralized Extracellular Matrix by Human Bone Marrow-Derived Stromal Cells In Vitro

Although controlled local inflammation is essential for adequate bone regeneration, several studies have shown that hyper-inflammatory conditions after major trauma are associated with impaired fracture healing. These hyper-inflammatory conditions include the trauma-induced systemic inflammatory response to major injury, open fractures, and significant injury to the surrounding soft tissues. The current literature suggests that increased or prolonged influx of neutrophils into the fracture hematoma may mediate impairment of bone regeneration after hyper-inflammatory conditions. The underlying mechanism remains unclear. We hypothesize that high neutrophil numbers inhibit synthesis of mineralized extracellular matrix (ECM) by bone marrow stromal cells (BMSCs). We therefore studied the effect of increasing concentrations of neutrophils on ECM synthesis by human BMSCs in vitro. Moreover, we determined how high neutrophil concentrations affect BMSC cell counts, as well as BMSC osteogenic activity determined by alkaline phosphatase (ALP) expression and ALP activity. Co-culture of BMSCs with neutrophils induced a 52% decrease in BMSC cell count (p < 0.01), a 64% decrease in the percentage of ALP+ cells (p < 0.001), a 28% decrease in total ALP activity (p < 0.01), and a significant decrease in the amount of mineralized ECM [38% decrease after 4 weeks (p < 0.05)]. Co-cultures with peripheral blood mononuclear cells and neutrophils within transwells did not induce a significant decrease in ALP activity. In conclusion, our data shows that a decreased amount of mineralized ECM became synthesized by BMSCs, when they were co-cultured with high neutrophil concentrations. Moreover, high neutrophil concentrations induced a decrease in BMSC cell counts and decreased ALP activity. Clarifying the underlying mechanism may contribute to development of therapies that augment bone regeneration or prevent impaired fracture healing after hyper-inflammatory conditions.

Biomaterials for revascularization and immunomodulation after spinal cord injury

Spinal cord injury (SCI) causes immediate damage to the nervous tissue accompanied by loss of motor and sensory function. The limited self-repair competence of injured nervous tissue underscores the need for reparative interventions to recover function after SCI. The vasculature of the spinal cord plays a crucial role in SCI and repair. Ruptured and sheared blood vessels in the injury epicenter and blood vessels with a breached blood-spinal cord barrier (BSCB) in the surrounding tissue cause bleeding and inflammation, which contribute to the overall tissue damage. The insufficient formation of new functional vasculature in and near the injury impedes endogenous tissue repair and limits the prospect of repair approaches. Limiting the loss of blood vessels, stabilizing the BSCB, and promoting the formation of new blood vessels are therapeutic targets for spinal cord repair. Inflammation is an integral part of injury-mediated vascular damage, which has deleterious and reparative consequences. Inflammation and the formation of new blood vessels are intricately interwoven. Biomaterials can be effectively used for promoting and guiding blood vessel formation or modulating the inflammatory response after SCI, thereby governing the extent of damage and the success of reparative interventions. This review deals with the vasculature after SCI, the reciprocal interactions between inflammation and blood vessel formation, and the potential of biomaterials to support revascularization and immunomodulation in damaged spinal cord nervous tissue.

Lignans From Forsythia x Intermedia Leaves and Flowers Attenuate the Pro-inflammatory Function of Leukocytes and Their Interaction With Endothelial Cells

Aim of the study: Taking into account that overactivated leukocytes are an important factor in the development of many chronic diseases, we investigated the activity of phytochemically characterized (HPLC-DAD-MSⁿ) extracts from forsythia leaves and flowers on the pro- and anti-inflammatory functions of leukocytes (effects on IL-1β, IL-8, TNF-α, and TGFβ release) and their adherence to endothelial cells. Using bio-guided fractionation, we isolated the active compounds and determined their biological activity, and we included the positive control quercetin. Methods: The effect on IL-1β, TNF-α, IL-8, and TGF-α production by leukocytes was measured by enzyme-linked immunosorbent assay (ELISA). The surface expression of adhesion molecules was analyzed with flow cytometry, and the neutrophil attachment to the endothelial cells was assessed fluorimetrically. The effects on p38MAPK, ERK1/2 and JNK phosphorylation were determined using western blots. Results: Leaf extracts had the effect of decreasing TNF-α production in neutrophils and monocyte/macrophage cells. The bio-guided fractionation led to the isolation of the following lignan aglycones: (+)-pinoresinol, (+)-epipinoresinol, (-)-matairesinol, (+)-phillygenin, and (-)-arctigenin. Only phillygenin was able to stimulate the anti-inflammatory function of macrophages by inducing TGF-β release and IL-10 receptor surface expression. Arctigenin, phillygenin, and a metabolite produced by the gut microbiota, enterolactone, decreased TNF-α and IL-1β production and neutrophil adhesion to endothelial cells, probably by attenuating the p38 and ERK kinase pathways. Conclusion:Forsythia x intermedia is a valuable source of active lignans, which may be potential candidates for treating inflammatory diseases that are associated with the excessive production of cytokines such as TNF-α and IL-1β.

A retrospective histopathological, immunohistochemical and molecular study of the presence of Leishmania spp. in the skin of cats with head and neck ulcerative dermatitis

BACKGROUND

Head and neck ulcers in cats can arise from allergic and nonallergic disorders, including feline leishmaniosis (FeL). It is important to rule out this aetiological agent in regions that are endemic for canine leishmaniosis, because the drugs used to treat immune-mediated disorders of cats can be contraindicated in the setting of infection.

HYPOTHESIS/OBJECTIVES

The aim of this study was to evaluate the skin of cats with ulcerative dermatitis of the head or neck for evidence of Leishmania infection using combined immunohistochemistry (IHC) and Polymerase Chain Reaction (PCR). An IHC for tissue histiocytes was also utilized because leishmaniosis may provoke a histiocytic inflammatory response.

ANIMALS

Twenty seven cats with head and/or neck ulcers.

METHODS

Skin biopsy specimens were examined for the presence of Leishmania spp. by routine histopathological evaluation and IHC using a polyclonal anti-Leishmania antibody, and by quantitative PCR (qPCR). The ionized calcium-binding adapter molecule-1 (IBA-1) antibody was used to immunolocalize histiocytes. Selected history and clinical data were recorded.

RESULTS

All specimens showed a superficial mid-perivascular mixed inflammatory infiltrate. The presence of histiocytes was confirmed in 23 of 27 cases with the IBA-1 antibody. Immunohistochemistry and qPCR techniques confirmed the absence of Leishmania in all cases.

CONCLUSIONS AND CLINICAL IMPORTANCE

Leishmania did not seem to play a role in the pathogenesis of feline ulcerative dermatitis of the head and neck in the subjects studied, despite a lifestyle potentially associated with infection. Histiocytic infiltration of tissue is not a specific marker for Leishmania infection in this population.

Roles of Macrophage Subtypes in Bowel Anastomotic Healing and Anastomotic Leakage

Macrophages play an important role in host defense, in addition to the powerful ability to phagocytose pathogens or foreign matters. They fulfill a variety of roles in immune regulation, wound healing, and tissue homeostasis preservation. Macrophages are characterized by high heterogeneity, which can polarize into at least two major extremes, M1-type macrophages (classical activation) which are normally derived from monocytes and M2-type macrophages (alternative activation) which are mostly those tissue-resident macrophages. Based on the wound healing process in skin, the previous studies have documented how these different subtypes of macrophages participate in tissue repair and remodeling, while the mechanism of macrophages in bowel anastomotic healing has not yet been established. This review summarizes the currently available evidence regarding the different roles of polarized macrophages in the physiological course of anastomotic healing and their pathological roles in anastomotic leakage, the most dangerous complication after gastrointestinal surgery.

Activation of Toll-like receptors in meconium aspiration syndrome

OBJECTIVE

Meconium aspiration syndrome (MAS) is a common cause of neonatal morbidity and mortality. Incomplete understanding of the pathogenesis of MAS has hindered the development of specific therapies. We hypothesized that activation of Toll-like receptors (TLRs) might play a role in the pathogenesis of MAS. The present study evaluated the expression of TLR 1, 4, 7, 8 and 9 in neonates with MAS.

STUDY DESIGN

The study included 39 neonates with MAS and 17 healthy gestational age-matched neonates as controls. Neonates with maternal chorioamnionitis, perinatal asphyxia, sepsis and congenital malformations were excluded. Good-quality total RNA from umbilical cord blood was reverse transcribed to prepare cDNA using Bio-Rad reverse transcription kit. This cDNA was used to study the expression status of TLR 1, 4, 7, 8 and 9 by real-time quantitative polymerase chain reaction.

RESULTS

Compared with controls, TLR1 and TLR4 were highly expressed, TLR9 was moderately expressed, TLR7 was weakly expressed and TLR8 expression was neutral in neonates with MAS. Within the MAS group, no difference in TLR expression was observed with respect to consistency of meconium, severity of the disease, oxygenation index and outcome.

CONCLUSION

There is activation of TLRs in neonates with MAS. We speculate that these TLRs probably act as endogenous ligands for various components of meconium that initiate the inflammatory cascade of MAS and contribute to its pathogenesis.

Combination of Pelargonium sidoides and Coptis chinensis root inhibits nuclear factor kappa B-mediated inflammatory response in vitro and in vivo

Background

Pelargonium sidoides (PS) and Coptis chinensis root (CR) have traditionally been used to treat various diseases, including respiratory and gastrointestinal infections, dysmenorrhea, and hepatic disorders. The present study was conducted to evaluate the anti-inflammatory effects of a combination of PS and CR in vitro and in vivo.

Methods

The in vitro effects of PS + CR on the induction of inflammation-related proteins were evaluated in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. The levels of nitric oxide (NO) and of inflammatory cytokines and prostaglandin E₂ (PGE₂) were measured using the Griess reagent and enzyme-linked immunosorbent assay (ELISA) methods, respectively. The expression of inflammation-related proteins was confirmed by Western blot. Additionally, the effects of PS + CR on paw edema volume, skin thickness, and numbers of infiltrated inflammatory cells, mast cells, COX-2-, iNOS-, and TNF-α-immunoreactive cells in dorsum and ventrum pedis skin were evaluated in a rat model of carrageenan (CA)-induced paw edema.

Results

PS + CR significantly reduced production of NO, PGE₂ and three pro-inflammatory cytokines (tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6) and also decreased levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Treatment with PS + CR significantly reduced the protein expression levels of LPS-stimulated nuclear factor kappa B (NF-κB) and phosphorylated inhibitor of NF-κB (p-I-κBα). Additionally, PS + CR significantly inhibited the increases in paw swelling, skin thickness, infiltrated inflammatory cells, mast cell degranulation, COX-2-, iNOS-, and TNF-α-immunoreactive cells in the rat model of CA-induced acute edematous paw.

Conclusions

These results demonstrate that PS + CR exhibits anti-inflammatory properties through decreasing the production of pro-inflammatory mediators (NO, PGE₂, TNF-α, IL-1β, and IL-6), suppressing NF-κB signaling in LPS-induced RAW 264.7 cells. Additionally, the results of the CA-induced rat paw edema assay revealed an anti-edema effect of PS + CR. Furthermore, it is suggested that PS + CR also inhibits acute edematous inflammation by suppressing mast cell degranulation and inflammatory mediators (COX-2, iNOS, and TNF-α). Thus, PS + CR may be a potential candidate for the treatment of various inflammatory diseases, and it may also contribute to a better understanding of the molecular mechanisms underlying inflammatory response regulation.

Reprogramming of pro-inflammatory human macrophages to an anti-inflammatory phenotype by bile acids

Cholestasis is caused by autoimmune reactions, drug-induced hepatotoxicity, viral infections of the liver and the obstruction of bile ducts by tumours or gallstones. Cholestatic conditions are associated with impaired innate and adaptive immunity, including alterations of the cellular functions of monocytes, macrophages, NK cells and T-cells. Bile acids act as signalling molecules, affecting lipopolysaccharide (LPS)-induced cytokine expression in primary human macrophages. The present manuscript investigates the impact of bile acids, such as taurolithocholic acid (TLC), on the transcriptome of human macrophages in the presence or absence of LPS. While TLC itself has almost no effect on gene expression under control conditions, this compound modulates the expression of 202 out of 865 transcripts in the presence of LPS. Interestingly, pathway analysis revealed that TLC specifically supressed the expression of genes involved in mediating pro-inflammatory effects, phagocytosis, interactions with pathogens and autophagy as well as the recruitment of immune cells, such as NK cells, neutrophils and T cells. These data indicate a broad influence of bile acids on inflammatory responses and immune functions in macrophages. These findings may contribute to the clinical observation that patients with cholestasis present a lack of response to bacterial or viral infections.

Ajuba receptor mediates the internalization of tumor-secreted GRP78 into macrophages through different endocytosis pathways

Glucose-regulated protein 78 (GRP78), an ER chaperone, is overexpressed in cancer cells. Solid tumor cells can secrete GRP78 that can promote tumor angiogenesis, differentiation of bone marrow-derived mesenchymal stem cells, tumor cell proliferation and polarization of tumor-associated macrophages. However, the mechanism by which GRP78 functions as a tumor promoter either by staying on the membrane to stimulate intracellular signals or directly entering into cytosolic remains unknown. Here, we reported that an endotoxin-free His-GRP78 protein was purified in vitro that simulates original secreted GRP78. Through analyzing GRP78 concentration in serum samples from 32 colon cancer patients, 40 nM His-GRP78 was selected as an optimized dose to treat cells. Biochemical analysis revealed that secreted GRP78 was able to enter into RAW264.7 and THP-1 cells directly rather than stay on the plasma membrane to transfer signals. Further studies showed that GRP78 internalization was endocytosis-dependent, and both phagocytosis and clathrin, caveolin-1 and micropinocytosis-mediated endocytosis pathways contributed to internalization of secreted GRP78 into cells. Mechanistically, Ajuba is able to interact with GRP78. Ablation of Ajuba suppressed the internalization of secreted GRP78 into cells, indicating that Ajuba was responsible for internalization of secreted GRP78 into RAW264.7. Furthermore, we observed that internalized GRP78 could entered into the mitochondrion and endoplasmic reticulum, which provided a suitable place and enough time for GRP78 to function in molecular and cellular processes. Together, these results reveal a novel mechanism by which secreted GRP78 internalizes into macrophages in the tumor microenvironment, which provides a potential target for drug development.

Novel identified aluminum hydroxide-induced pathways prove monocyte activation and pro-inflammatory preparedness

Aluminum-based adjuvants are the most widely used adjuvants in human vaccines. A comprehensive understanding of the mechanism of action of aluminum adjuvants at the molecular level, however, is still elusive. Here, we unravel the effects of aluminum hydroxide Al(OH)₃ by a systems-wide analysis of the Al(OH)₃-induced monocyte response. Cell response analysis by cytokine release was combined with (targeted) transcriptome and full proteome analysis. Results from this comprehensive study revealed two novel pathways to become activated upon monocyte stimulation with Al(OH)₃: the first pathway was IFNβ signaling possibly induced by DAMP sensing pathways like TLR or NOD1 activation, and second the HLA class I antigen processing and presentation pathway. Furthermore, known mechanisms of the adjuvant activity of Al(OH)₃ were elucidated in more detail such as inflammasome and complement activation, homeostasis and HLA-class II upregulation, possibly related to increased IFNγ gene expression. Altogether, our study revealed which immunological pathways are activated upon stimulation of monocytes with Al(OH)₃, refining our knowledge on the adjuvant effect of Al(OH)₃ in primary monocytes.

SIGNIFICANCE

Aluminum salts are the most used adjuvants in human vaccines but a comprehensive understanding of the working mechanism of alum adjuvants at the molecular level is still elusive. Our Systems Vaccinology approach, combining complementary molecular biological, immunological and mass spectrometry-based techniques gave a detailed insight in the molecular mechanisms and pathways induced by Al(OH)₃ in primary monocytes. Several novel immunological relevant cellular pathways were identified: type I interferon secretion potentially induced by TLR and/or NOD like signaling, the activation of the inflammasome and the HLA Class-I and Class-II antigen presenting pathways induced by IFNγ. This study highlights the mechanisms of the most commonly used adjuvant in human vaccines by combing proteomics, transcriptomics and cytokine analysis revealing new potential mechanisms of action for Al(OH)₃.

Adjuvants

Developing new vaccines against emerging pathogens or pathogens where variability of antigenic sites presents a challenge, the inclusion of stimulators of the innate immune system is critical to mature the immune response in a way that allows high avidity recognition while preserving the ability to react to drifted serovars. The innate immune system is an ancient mechanism for recognition of nonself and the first line of defense against pathogen insult. By triggering innate receptors, adjuvants can boost responses to vaccines and enhance the quality and magnitude of the resulting immune response. This chapter: (1) describes the innate immune system, (2) provides examples of how adjuvants are formulated to optimize their effectiveness, and (3) presents examples of how adjuvants can improve outcomes of immunization.

ATP Evokes Ca2+ Responses and CXCL5 Secretion via P2X4 Receptor Activation in Human Monocyte-Derived Macrophages

Leukocytes sense extracellular ATP, a danger-associated molecular pattern, released during cellular stress and death, via activation of cell surface P2X and P2Y receptors. Here, we investigate P2 receptor expression in primary human monocyte-derived macrophages and receptors that mediate ATP-evoked intracellular [Ca²⁺]_i signals and cytokine production in response to ATP concentrations that exclude P2X₇ receptor activation. Expression of P2X₁, P2X₄, P2X₅, P2X₇, P2Y₁, P2Y₂, P2Y₄, P2Y₆, P2Y₁₁, and P2Y₁₃ was confirmed by quantitative RT-PCR and immunocytochemistry. ATP elicited intracellular Ca²⁺ responses in a concentration-dependent fashion (EC₅₀ = 11.4 ± 2.9 μM, n = 3). P2Y₁₁ and P2Y₁₃ activations mediated the amplitude of [Ca²⁺]_i response, whereas P2X₄ activation, but not P2X₁ or P2X₇, determined the duration of Ca²⁺ response during a sustained phase. ATP mediated gene induction of CXCL5, a proinflammatory chemokine. P2X₄ antagonism (PSB-12062 or BX430) inhibited ATP-mediated induction of CXCL5 gene expression and secretion of CXCL5 by primary macrophage. Inhibition of CXCL5 secretion by P2X₄ antagonists was lost in the absence of extracellular Ca²⁺ Reciprocally, positive allosteric modulation of P2X₄ (ivermectin) augmented ATP-mediated CXCL5 secretion. P2X₇, P2Y₁₁, or P2Y₁₃ receptor did not contribute to CXCL5 secretion. Together, the data reveals a role for P2X₄ in determining the duration of ATP-evoked Ca²⁺ responses and CXCL5 secretion in human primary macrophage.

Immunological challenges associated with artificial skin grafts: available solutions and stem cells in future design of synthetic skin

The repair or replacement of damaged skins is still an important, challenging public health problem. Immune acceptance and long-term survival of skin grafts represent the major problem to overcome in grafting given that in most situations autografts cannot be used. The emergence of artificial skin substitutes provides alternative treatment with the capacity to reduce the dependency on the increasing demand of cadaver skin grafts. Over the years, considerable research efforts have focused on strategies for skin repair or permanent skin graft transplantations. Available skin substitutes include pre- or post-transplantation treatments of donor cells, stem cell-based therapies, and skin equivalents composed of bio-engineered acellular or cellular skin substitutes. However, skin substitutes are still prone to immunological rejection, and as such, there is currently no skin substitute available to overcome this phenomenon. This review focuses on the mechanisms of skin rejection and tolerance induction and outlines in detail current available strategies and alternatives that may allow achieving full-thickness skin replacement and repair.

Dihydrofisetin exerts its anti-inflammatory effects associated with suppressing ERK/p38 MAPK and Heme Oxygenase-1 activation in lipopolysaccharide-stimulated RAW 264.7 macrophages and carrageenan-induced mice paw edema

Dihydrofisetin is a flavanonol derived from some edible wild herbs and traditional Chinese medicines. It has been found to possess many biological activities. However, the anti-inflammatory potential of Dihydrofisetin remains uncharacterized. The aim of the present study was to investigate the anti-inflammatory activity of Dihydrofisetin and its underlying mechanisms. We found that Dihydrofisetin dose-dependently inhibited lipopolysaccharide-induced productions of nitric oxide (NO) and prostaglandin E₂ (PGE₂) in RAW 264.7 macrophages, probably through suppressing the protein expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). The expressions of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) and monocyte chemotactic protein (MCP-1) were also suppressed. We further demonstrated that Dihydrofisetin inhibited the activation of mitogen-activated protein kinases (MAPKs) pathway and phosphorylation of IκB-α whereas upregulated the expression of heme oxygenase-1 (HO-1). The in vivo carrageenan-induced mice paw edema study also indicated that treatment with 100 mg/kg of Dihydrofisetin could significantly inhibit carrageenan induced paw edema, decrease the levels of TNF-α, IL-6 and MDA, and increase the activity of GSH-Px in paw tissues. Taken together, Dihydrofisetin may act as a natural agent for treating inflammatory diseases by targeting MAPK, NF-κB and HO-1 pathways.

Finasteride accelerates prostate wound healing after thulium laser resection through DHT and AR signalling

OBJECTIVES

Urinary tract infection, urinary frequency, urgency, urodynia and haemorrhage are common post-operative complications of thulium laser resection of the prostate (TmLRP). Our study mainly focuses on the role of finasteride in prostate wound healing through AR signalling.

MATERIALS AND METHODS

TmLRP beagles were randomly distributed into different treatment groups. Serum and intra-prostatic testosterone and DHT level were determined. Histological analysis was conducted to study the re-epithelialization and inflammatory response of the prostatic urethra in each group. We investigated the role of androgen in proliferation and inflammatory response in prostate. In addition, the effects of TNF-α on prostate epithelium and stromal cells were also investigated.

RESULTS

Testosterone and DHT level increased in testosterone group and DHT decreased in finasteride group. Accelerated wound healing of prostatic urethra was observed in the finasteride group. DHT suppressed proliferation of prostate epithelium and enhanced inflammatory response in prostate. We confirmed that DHT enhanced macrophages TNF-α secretion through AR signalling. TNF-α suppressed proliferation of prostate epithelial cells and retarded cell migration. TNF-α also played a pivotal role in suppressing fibroblasts activation and contraction.

CONCLUSION

Testosterone treatment repressed re-epithelialization and wound healing of prostatic urethra. Finasteride treatment may be an effective way to promote prostate re-epithelialization.

Exogenous oxidants activate nuclear factor kappa B through Toll-like receptor 4 stimulation to maintain inflammatory phenotype in macrophage

Disturbances in redox equilibrium in tissue can lead to inflammatory state, which is a mediatory factor in many human diseases. The mechanism(s) by which exogenous oxidants may activate an inflammatory response is not fully understood. Emerging evidence suggests that oxidant-induced Toll-like receptor 4 (TLR4) activation plays a major role in "sterile" inflammation. In the present study, we used murine macrophage RAW-Blue cells, which are chromosomally integrated with secreted embryonic alkaline phosphatase (SEAP) inducible by NF-κB. We confirmed the expression of TLR4 mRNA and protein in RAW-Blue cells by RT-PCR and Western blot, respectively. We showed that oxidants increased intracellular reactive oxygen species production and lipid peroxidation, which resulted in decreased intracellular total antioxidant capacity. Consistent with the actions of TLR4-specific agonist LPS-EK, exogenous oxidants increased transcriptional activity of NF-κB p65 with subsequent release of NF-κB reporter gene SEAP. These effects were blocked by pretreatment with TLR4 neutralizing pAb and TLR4 signaling inhibitor CLI-095. In addition, oxidants decreased the expression of IκBα with enhanced phosphorylation at the Tyr42 residue. Finally, oxidants and LPS-EK increased TNFα production, but did not affect IL-10 production, which may cause imbalance between pro- and anti-inflammatory processes, which CLI-095 inhibited. For biological relevance, we confirmed that oxidants increased release of TNFα and IL-6 in primary macrophages derived from TLR4-WT and TLR4-KO mice. Our results support the involvement of TLR4 mediated oxidant-induced inflammatory phenotype through NF-κB activation in macrophages. Thus exogenous oxidants may play a role in activating inflammatory phenotypes that propagate and maintain chronic disease states.

Harnessing the cross-talk between tumor cells and tumor-associated macrophages with a nano-drug for modulation of glioblastoma immune microenvironment

Glioblastoma (GBM) is the most frequent and malignant brain tumor with a high mortality rate. The presence of a large population of macrophages (Mφ) in the tumor microenvironment is a prominent feature of GBM and these so-called tumor-associated Mφ (TAM) closely interact with the GBM cells to promote the survival, progression and therapy resistance of the GBM. Various therapeutic strategies have been devised either targeting the GBM cells or the TAM but few have addressed the cross-talks between the two cell populations. The present study was carried out to explore the possibility of exploiting the cross-talks between the GBM cells (GC) and TAM for modulation of the GBM microenvironment through using Nano-DOX, a drug composite based on nanodiamonds bearing doxorubicin. In the in vitro work on human cell models, Nano-DOX-loaded TAM were first shown to be viable and able to infiltrate three-dimensional GC spheroids and release cargo drug therein. GC were then demonstrated to encourage Nano-DOX-loaded TAM to unload Nano-DOX back into GC which consequently emitted damage-associated molecular patterns (DAMPs) that are powerful immunostimulatory agents as well as indicators of cell damage. Nano-DOX was next proven to be a more potent inducer of GC DAMPs emission than doxorubicin. As a result, Nano-DOX-damaged GC exhibited an enhanced ability to attract both TAM and Nano-DOX-loaded TAM. Most remarkably, Nano-DOX-damaged GC reprogrammed the TAM from a pro-GBM phenotype to an anti-GBM phenotype that suppressed GC growth. Finally, the in vivo relevance of the in vitro findings was tested in animal study. Mice bearing orthotopic human GBM xenografts were intravenously injected with Nano-DOX-loaded mouse TAM which were found releasing drug in the GBM xenografts 24h after injection. GC damage was evidenced by the induction of DAMPs emission within the xenografts and a shift of TAM phenotype was detected as well. Taken together, our results demonstrate a novel way with therapeutic potential to harness the cross-talk between GBM cells and TAM for modulation of the tumor immune microenvironment.

Anti-inflammatory effects of Daehwangmokdantang, a traditional herbal formulation, in lipopolysaccharide-stimulated RAW 264.7 macrophages

Daehwangmokdantang (DHMDT) is a traditional polyherbal formulation that has known antidiarrheal and anti-inflammatory activities. However, the underlying mechanisms of these activities are poorly understood. In the present study, the inhibitory effects of DHMDT on the production of proinflammatory mediators and cytokines in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages were investigated. The inhibitory effects of DHMDT on LPS-induced nitric oxide (NO), prostaglandin (PG)E₂, tumor necrosis factor (TNF)-α and interleukin (IL)-1β production were examined using Griess reagent and ELISA detection kits. The effects of DHMDT on the expression of inducible NO synthase (iNOS), cyclooxygenase (COX)-2, IL-1β and TNF-α, and their upstream signal proteins, including nuclear factor (NF)-κB, mitogen-activated protein kinases (MAPKs) and RAC-α serine/threonine-protein kinase (Akt), a phosphatidylinositol 3-kinase (PI3K) downstream effector, were investigated using western blotting and immunofluorescence staining. The results revealed the pretreatment with DHMDT significantly inhibited the LPS-induced production of NO, PGE₂, TNF-α, and IL-1β, and expression of iNOS, COX-2 TNF-α, and IL-1β, without any significant cytotoxicity. DHMDT also efficiently prevented the translocation of the NF-κB subunit p65 into the nucleus by interrupting the activation of the upstream mediator inhibitor of NF-κB kinase α/β. Furthermore, the anti-inflammatory effects of DHMDT were associated with the suppression of LPS-induced phosphorylation of Akt and MAPKs in RAW 264.7 macrophages. Therefore, the results of the present study indicate that DHMDT exhibited anti-inflammatory activity via the inhibition of proinflammatory mediators and cytokines, in which the inactivation of NF-κB, PI3K/Akt, and MAPKs may be involved. These results suggest that DHMDT may be a potential anti-inflammatory drug candidate.

Macrophage-Associated Osteoactivin/GPNMB Mediates Mesenchymal Stem Cell Survival, Proliferation, and Migration Via a CD44-Dependent Mechanism

Although MSCs have been widely recognized to have therapeutic potential in the repair of injured or diseased tissues, it remains unclear how functional activities of mesenchymal stem cells (MSCs) are influenced by the surrounding inflammatory milieu at the site of tissue injury. Macrophages constitute an essential component of innate immunity and have been shown to exhibit a phenotypic plasticity in response to various stimuli, which play a central role in both acute inflammation and wound repair. Osteoactivin (OA)/Glycoprotein non-metastatic melanoma protein B (GPNMB), a transmembrane glycoprotein that plays a role in cell differentiation, survival, and angiogenesis. The objective of this study was to investigate the potential role of OA/GPNMB in macrophage-induced MSC function. We found that reparative M2 macrophages express significantly greater levels of OA/GPNMB than pro-inflammatory M1 macrophages. Furthermore, using loss of function and rescue studies, we demonstrated that M2 macrophages-secreted OA/GPNMB positively regulates the viability, proliferation, and migration of MSCs. More importantly, we demonstrated that OA/GPNMB acts through ERK and AKT signaling pathways in MSCs via CD44, to induce these effects. Taken together, our results provide pivotal insight into the mechanism by which OA/GPNMB contributes to the tissue reparative phenotype of M2 macrophages and positively regulates functional activities of MSCs. J. Cell. Biochem. 117: 1511-1521, 2016. © 2015 Wiley Periodicals, Inc.

A past and present overview of macrophage metabolism and functional outcomes

In 1986 and 1987, Philip Newsholme et al. reported macrophages utilize glutamine, as well as glucose, at high rates. These authors measured key enzyme activities and consumption and production levels of metabolites in incubated or cultured macrophages isolated from the mouse or rat intraperitoneal cavity. Metabolic pathways essential for macrophage function were then determined. Macrophages utilize glucose to generate (i) ATP in the pathways of glycolysis and mitochondrial oxidative phosphorylation, (ii) glycerol 3-phosphate for the synthesis of phospholipids and triacylglycerols, (iii) NADPH for the production of reactive oxygen species (ROS) and (iv) ribose for the synthesis of RNA and subsequently production and secretion of protein mediators (e.g. cytokines). Glutamine plays an essential role in macrophage metabolism and function, as it is required for energy production but also provides nitrogen for synthesis of purines, pyrimidines and thus RNA. Macrophages also utilize fatty acids for both energy production in the mitochondria and lipid synthesis essential to plasma membrane turnover and lipid meditator production. Recent studies utilizing metabolomic approaches, transcriptional and metabolite tracking technologies have detailed mitochondrial release of tricarboxylic acid (TCA) intermediates (e.g. citrate and succinate) to the cytosol, which then regulate pro-inflammatory responses. Macrophages can reprogramme their metabolism and function according to environmental conditions and stimuli in order to polarize phenotype so generating pro- or anti-inflammatory cells. Changes in macrophage metabolism result in modified function/phenotype and vice versa. The plasticity of macrophage metabolism allows the cell to quickly respond to changes in environmental conditions such as those induced by hormones and/or inflammation. A past and present overview of macrophage metabolism and impact of endocrine regulation and the relevance to human disease are described in this review.

Macrophage Phenotypes Regulate Scar Formation and Chronic Wound Healing

Macrophages and inflammation play a beneficial role during wound repair with macrophages regulating a wide range of processes, such as removal of dead cells, debris and pathogens, through to extracellular matrix deposition re-vascularisation and wound re-epithelialisation. To perform this range of functions, these cells develop distinct phenotypes over the course of wound healing. They can present with a pro-inflammatory M1 phenotype, more often found in the early stages of repair, through to anti-inflammatory M2 phenotypes that are pro-repair in the latter stages of wound healing. There is a continuum of phenotypes between these ranges with some cells sharing phenotypes of both M1 and M2 macrophages. One of the less pleasant consequences of quick closure, namely the replacement with scar tissue, is also regulated by macrophages, through their promotion of fibroblast proliferation, myofibroblast differentiation and collagen deposition. Alterations in macrophage number and phenotype disrupt this process and can dictate the level of scar formation. It is also clear that dysregulated inflammation and altered macrophage phenotypes are responsible for hindering closure of chronic wounds. The review will discuss our current knowledge of macrophage phenotype on the repair process and how alterations in the phenotypes might alter wound closure and the final repair quality.

Anti-Inflammatory Activity of Citric Acid-Treated Wheat Germ Extract in Lipopolysaccharide-Stimulated Macrophages

Until recently, fermentation was the only processing used to improve the functionality of wheat germ. The release of 2,6-dimethoxy-1,4-benzoquinone (DMBQ) from hydroquinone glycosides during the fermentation process is considered a marker of quality control. Here, we treated wheat germ extract with citric acid (CWG) to release DMBQ and examined the anti-inflammatory activity of this extract using a lipopolysaccharide-activated macrophage model. Treatment of wheat germ with citric acid resulted in detectable release of DMBQ but reduced total phenolic and total flavonoid contents compared with untreated wheat germ extract (UWG). CWG inhibited secretion of the pro-inflammatory cytokines tumor necrosis factor-α, interleukin (IL)-6, and IL-12 and the synthesis of cyclooxygenase-2, while UWG only decreased IL-12 production. CWG and UWG induced high levels of anti-inflammatory IL-10 and heme oxygenase-1. CWG specifically inhibited phosphorylation of NF-κB p65 and p38 kinase at 15 min after LPS stimulation. Our study showed that citric acid treatment enhanced the anti-inflammatory activity of wheat germ extract.

Pathological manifestations in lymphatic filariasis correlate with lack of inhibitory properties of IgG4 antibodies on IgE-activated granulocytes

Helminth parasites are known to be efficient modulators of their host's immune system. To guarantee their own survival, they induce alongside the classical Th2 a strong regulatory response with high levels of anti-inflammatory cytokines and elevated plasma levels of IgG4. This particular antibody was shown in different models to exhibit immunosuppressive properties. How IgG4 affects the etiopathology of lymphatic filariasis (LF) is however not well characterized. Here we investigate the impact of plasma and affinity-purified IgG/IgG4 fractions from endemic normals (EN) and LF infected pathology patients (CP), asymptomatic microfilaraemic (Mf+) and amicrofilaraemic (Mf-) individuals on IgE/IL3 activated granulocytes. The activation and degranulation states were investigated by monitoring the expression of CD63/HLADR and the release of granule contents (neutrophil elastase (NE), eosinophil cationic protein (ECP) and histamine) respectively by flow cytometry and ELISA. We could show that the activation of granulocytes was inhibited in the presence of plasma from EN and Mf+ individuals whereas those of Mf- and CP presented no effect. This inhibitory capacity was impaired upon depletion of IgG in Mf+ individuals but persisted in IgG-depleted plasma from EN, where it strongly correlated with the expression of IgA. In addition, IgA-depleted fractions failed to suppress granulocyte activation. Strikingly, affinity-purified IgG4 antibodies from EN, Mf+ and Mf- individuals bound granulocytes and inhibited activation and the release of ECP, NE and histamine. In contrast, IgG4 from CP could not bind granulocytes and presented no suppressive capacity. Reduction of both the affinity to, and the suppressive properties of anti-inflammatory IgG4 on granulocytes was reached only when FcγRI and II were blocked simultaneously. These data indicate that IgG4 antibodies from Mf+, Mf- and EN, in contrast to those of CP, natively exhibit FcγRI/II-dependent suppressive properties on granulocytes. Our findings suggest that quantitative and qualitative alterations in IgG4 molecules are associated with the different clinical phenotypes in LF endemic regions.

3'UTR AU-Rich Elements (AREs) and the RNA-Binding Protein Tristetraprolin (TTP) Are Not Required for the LPS-Mediated Destabilization of Phospholipase-Cβ-2 mRNA in Murine Macrophages

We have shown previously that bacterial lipopolysaccharide (LPS)-mediated suppression of phospholipase-Cβ-2 (PLCβ-2) expression is involved in M1 (inflammatory) to M2-like (wound healing) phenotypic switching of macrophages triggered by adenosine. This suppression is mediated post-transcriptionally by destabilization of PLCβ-2 mRNA (messenger ribonucleic acid). To investigate the mechanism of this LPS-mediated destabilization, we examined the roles of RNA-binding agents including microRNAs and RNA-binding proteins that are involved in regulating stability of mRNAs encoding growth factors, inflammatory mediators, and proto-oncogenes. Adenylate and uridylate (AU)-rich elements (AREs) in 3'UTRs are specific recognition sites for RNA-binding proteins including tristetraprolin (TTP), HuR, and AUF1 and for microRNAs that are involved in regulating mRNA stability. In this study, we investigated the role of TTP and AREs in regulating PLCβ-2 mRNA stability. The 3'UTR of the PLCβ-2 gene was inserted into the pLightswitch luciferase reporter plasmid and transfected into RAW264.7 cells. LPS suppressed luciferase expression from this reporter. Luciferase expression from mutant 3'UTR constructs lacking AREs was similarly downregulated, suggesting that these regions are not required for LPS-mediated suppression of PLCβ-2. TTP was rapidly upregulated in both primary murine macrophages and RAW264.7 cells in response to LPS. Suppression of PLCβ-2 by LPS was examined using macrophages from mice lacking TTP (TTP^-/-). LPS suppressed PLCβ-2 expression to the same extent in wild type (WT) and TTP^-/- macrophages. Also, the rate of decay of PLCβ-2 mRNA in LPS-treated macrophages following transcriptional blockade was similar in WT and TTP^-/- macrophages, clearly indicating that TTP is not involved in LPS-mediated destabilization of PLCβ-2 mRNA in macrophages.

Corylin protects LPS-induced sepsis and attenuates LPS-induced inflammatory response

Corylin is a main compound isolated from Psoralea corylifolia L. (Fabaceae). A variety of pharmacological effects such as antioxidant, anti-proliferation, and anti-inflammatory properties of corylin have been reported. Nevertheless, the effect of corylin in microbial infection and sepsis remains unclear. In the present study, we investigated the anti-inflammatory effects of corylin. Our experimental results demonstrated that corylin inhibited the production of TNF-α, IL-6 and NO by both LPS-activated RAW 264.7 cells and LPS-activated murine peritoneal macrophages. Moreover, corylin suppressed the expression levels of iNOS and COX-2, reduced the production of PGE₂ and HMGB1, blocked the translocation of HMGB1 from the nucleus to cytosol, and decreased the phosphorylation of MAPKs in LPS-activated RAW 264.7 cells as well as suppressed the activity of NF-κB in LPS-activated J-Blue cells. In addition, the administration of corylin reduced the production of NO and TNF-α, decreased LPS-induced liver damage markers (AST and ALT) and kidney damage markers (BUN and CRE), attenuated infiltration of inflammatory cells and tissue damage of lung, liver and kidney, and enhanced the survival rate of LPS-challenged mice. Taken together, these results show the anti-inflammatory properties of corylin on LPS-induced inflammation and sepsis. Corylin could potentially be a novel anti-inflammatory and immunosuppressive drug candidate in the treatment of sepsis and septic shock.

Doxorubicin inhibits muscle inflammation after eccentric exercise

BACKGROUND

Doxorubicin, a widely used anti-tumour drug, is known to cause muscle loss in cancer patients.

METHODS

Following an acute dose of doxorubicin injection (2.5 mg/kg per body weight), we examined macrophage distribution in rat soleus muscle challenged by eccentric exercise (downhill running). Long-term doxorubicin treatment (one injection every 3 days) on muscle mass and survival were also determined.

RESULTS

Under non-exercised condition, increased tumour necrosis factor (TNF)-alpha mRNA and decreased IL-10 mRNA were observed in soleus muscle of doxorubicin-treated rats, compared with saline-treated control rats. However, increases in inflammation score (leukocyte infiltration), nitrotyrosine level, and M1 macrophage (CD68⁺ ) invasion in exercised soleus muscle were absent in doxorubicin-treated rats, whereas increased M2 macrophage (CD163⁺ ) localization in exercised muscle was less affected by doxorubicin. Despites coenzyme Q (Q10) supplementation significantly elevated TNF-alpha mRNA, nitrotyrosine, and anti-oxidant gamma-glutamylcysteine synthetase (GCS) levels in non-exercised soleus muscle, these pro-inflammatory responses were also abolished in doxorubicin-treated rats. Results from long-term doxorubicin treatment show a significant muscle loss followed by an accelerated death, which cannot be reversed by Q10 supplementation.

CONCLUSIONS

(i) Doxorubicin impairs inflammation mechanism by depleting M1 macrophage in exercised skeletal muscle; (ii) Muscle loss and accelerated death during prolonged doxorubicin treatment cannot be reversed by Q10 supplementation.

Pathophysiology of Pediatric Multiple Organ Dysfunction Syndrome

OBJECTIVE

To describe the pathophysiology associated with multiple organ dysfunction syndrome in children.

DATA SOURCES

Literature review, research data, and expert opinion.

STUDY SELECTION

Not applicable.

DATA EXTRACTION

Moderated by an experienced expert from the field, pathophysiologic processes associated with multiple organ dysfunction syndrome in children were described, discussed, and debated with a focus on identifying knowledge gaps and research priorities.

DATA SYNTHESIS

Summary of presentations and discussion supported and supplemented by relevant literature.

CONCLUSIONS

Experiment modeling suggests that persistent macrophage activation may be a pathophysiologic basis for multiple organ dysfunction syndrome. Children with multiple organ dysfunction syndrome have 1) reduced cytochrome P450 metabolism inversely proportional to inflammation; 2) increased circulating damage-associated molecular pattern molecules from injured tissues; 3) increased circulating pathogen-associated molecular pattern molecules from infection or endogenous microbiome; and 4) cytokine-driven epithelial, endothelial, mitochondrial, and immune cell dysfunction. Cytochrome P450s metabolize endogenous compounds and xenobiotics, many of which ameliorate inflammation, whereas damage-associated molecular pattern molecules and pathogen-associated molecular pattern molecules alone and together amplify the cytokine production leading to the inflammatory multiple organ dysfunction syndrome response. Genetic and environmental factors can impede inflammation resolution in children with a spectrum of multiple organ dysfunction syndrome pathobiology phenotypes. Thrombocytopenia-associated multiple organ dysfunction syndrome patients have extensive endothelial activation and thrombotic microangiopathy with associated oligogenic deficiencies in inhibitory complement and a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13. Sequential multiple organ dysfunction syndrome patients have soluble Fas ligand-Fas-mediated hepatic failure with associated oligogenic deficiencies in perforin and granzyme signaling. Immunoparalysis-associated multiple organ dysfunction syndrome patients have impaired ability to resolve infection and have associated environmental causes of lymphocyte apoptosis. These inflammation phenotypes can lead to macrophage activation syndrome. Resolution of multiple organ dysfunction syndrome requires elimination of the source of inflammation. Full recovery of organ functions is noted 6-18 weeks later when epithelial, endothelial, mitochondrial, and immune cell regeneration and reprogramming is completed.

Changes in protein expression after treatment with Ancylostoma caninum excretory/secretory products in a mouse model of colitis

Different reports have highlighted the potential use of helminths and their secretions in the treatment of inflammatory bowel disease (IBD) conditions; however, no reports have investigated their effects at a proteome level. Herein, we characterise the protein expression changes that occur in lamina propria (LP) and the intestinal epithelial cells (IEC) of mice with dextran sulfate sodium (DSS)-induced colitis treated with Ancylostoma caninum excretory/secretory (ES) products using a quantitative proteomic approach. We have shown how parasite products can significantly alter the expression of proteins involved in immune responses, cell death and with an antioxidant activity. Interestingly, significant changes in the expression levels of different mucins were observed in this study. MUC13, a mucin implicated in gastrointestinal homeostasis, was upregulated in the LP of mice with DSS-induced colitis treated with ES, while MUC2, a major component of mucus, was upregulated in the IEC. In addition, A. caninum proteins have an important effect on proteins with antioxidant functions and proteins involved in intestinal homeostasis and tissue integrity and regeneration. Understanding how parasites can ameliorate IBD pathogenesis can help us design novel treatments for autoimmune diseases.

Contributions of transferrin to acute inflammation in the goldfish, C. auratus

Transferrin is an evolutionary conserved protein that in addition to having a critical role in iron transport also has been shown to have a crucial role in host defence, by depriving iron from invading pathogens. Recently cleaved transferrin products was shown to activate macrophages in vitro. We now use an in vivo model of self-resolving peritonitis in goldfish, coupled with gene expression and protein analysis to evaluate the contributions of cleaved transferrin to acute inflammation. We show, for the first time, that cleaved transferrin products are produced in vivo early during an acute inflammatory response. These cleaved transferrin fragments were produced during pathogen-induced, but not sterile, inflammation. Both macrophages and neutrophils were able to contribute to transferrin cleavage. However, only macrophages contributed to this innate process through inducible expression of transferrin. The appearance of transferrin cleavage products in vivo correlated with the influx of leukocytes but did not necessarily correlate the induction of robust respiratory burst and nitric oxide responses. Overall, this study adds to a growing body of work highlighting the role of transferrin as an immune regulator during acute inflammation. Given the significant conservation of this and related molecules, these findings have potentially broad implications for host defences and inflammation control across evolution.

Nitric oxide-activatable gold nanoparticles for specific targeting and photo-thermal ablation of macrophages

Nitric oxide-activatable gold nanoparticles can be utilized as a useful NO sensing tool and a photo-thermal agent for specific inflammation-associated macrophages.

Testing the biological embedding hypothesis: Is early life adversity associated with a later proinflammatory phenotype?

Accumulating evidence suggests that the experience of early life adversity is a risk factor for a range of poor outcomes across development, including poor physical health in adulthood. The biological embedding model of early adversity (Miller, Chen, & Parker, 2011) suggests that early adversity might become embedded within immune cells known as monocytes/macrophages, programming them to be overly aggressive to environmental stimuli and insensitive to inhibitory signals, creating a "proinflammatory phenotype" that increases vulnerability to chronic diseases across the life span. We tested this hypothesis in the present study. Adolescent girls (n = 147) had blood drawn every 6 months across a 2.5-year period. To assess inflammatory responses to challenge, their monocytes were stimulated in vitro with a bacterial product, and production of the cytokine interleukin-6 was quantified. Hydrocortisone was added to cultures to assess the cells' sensitivity to glucocorticoids' anti-inflammatory signal. Using cluster analyses, we found that early life adversity was associated with greater odds of displaying a proinflammatory phenotype characterized by relatively larger interleukin-6 responses and relatively less sensitivity to glucocorticoids. In contrast, ongoing social stress was not associated with increasing odds of being categorized in the proinflammatory cluster. These findings suggest that early life adversity increases the probability of developing a proinflammatory phenotype, which, if sustained, could forecast risk for health problems later in life.

Effects of xenoestrogens in human M1 and M2 macrophage migration, cytokine release, and estrogen-related signaling pathways

Bisphenol A (BPA), bis(2-ethylhexyl)phthalate (DEHP) and di(n-butyl)phthalate (DBP) are environmental estrogens that have been associated with a wide range of adverse health outcomes for which inflammation has also been hypothesized as a potentially involved mechanism and where macrophages play a central role. This study was carried out to evaluate if xenoestrogen (XE) treatment of classically (M1) or alternatively (M2) activated macrophages could affect their behavior. For this purpose, human peripheral blood monocyte-derived macrophages either unstimulated or activated with lipopolysaccharide (100 ng/mL, M1) or with interleukin (IL) 4 (15 ng/mL, M2) were treated with 17β-estradiol (E₂ ), BPA, DEHP and DBP alone or in combination with selective ERα or ERβ antagonists. Migratory capability, cytokine release, and estrogen-associated signaling pathways were evaluated to assess macrophage function. All tested XEs had a tendency to stimulate M2 migration, an effect that followed the same direction than E₂ . Moreover, all XEs significantly induced IL10 in M1 and decreased IL6 and globally decreased IL10, IL6, TNFα, and IL1β release by M2 macrophages. However, DEHP and DBP significantly increased IL1β release in M1 and M2 macrophages, respectively. Some of the effects described above were shown to be mediated by either ERα or ERβ and were simultaneous to modulation of NF-κB, AP1, JNK, or ERK signaling pathways. We provide new evidence of the effect of XE on macrophage behavior and their mechanisms with relevance to the understanding of the action of environmental chemicals on the immune system and inflammation-associated diseases. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1496-1509, 2016.

Sakuranetin Inhibits Inflammatory Enzyme, Cytokine, and Costimulatory Molecule Expression in Macrophages through Modulation of JNK, p38, and STAT1

Sakuranetin is flavonoid phytoalexin that serves as a plant antibiotic and exists in Prunus and several other plant species. Recently, we identified the anti-inflammatory effect of Prunus yedoensis and found that there were few studies on the potential anti-inflammatory activity of sakuranetin, one of the main constituents of Prunus yedoensis. Here, we isolated peritoneal macrophages from thioglycollate-injected mice and examined whether sakuranetin affected the response of the macrophages in response to lipopolysaccharide (LPS) plus interferon- (IFN-) γ or LPS only. Sakuranetin suppressed the synthesis of iNOS and COX2 in LPS/IFN-γ stimulated cells and the secretion of TNF-α, IL-6, and IL-12 in LPS stimulated cells. The surface expression of the costimulatory molecules, CD86 and CD40, was also decreased. Among the LPS-induced signaling molecules, STAT1, JNK, and p38 phosphorylation was attenuated. These findings are evidence that sakuranetin acts as anti-inflammatory flavonoid and further study is required to evaluate its in vivo efficacy.

The impact of hypoxia on tumor-associated macrophages

The role of tumor-associated macrophages (TAMs) in cancer is often correlated with poor prognosis, even though this statement should be interpreted with care, as the effects of macrophages primarily depend on their localization within the tumor. This versatile cell type orchestrates a broad spectrum of biological functions and exerts very complex and even opposing functions on cell death, immune stimulation or suppression, and angiogenesis, resulting in an overall pro- or antitumoral effect. We are only beginning to understand the environmental cues that contribute to transient retention of macrophages in a specific phenotype. It has become clear that hypoxia shapes and induces specific macrophage phenotypes that serve tumor malignancy, as hypoxia promotes immune evasion, angiogenesis, tumor cell survival, and metastatic dissemination. Additionally, TAMs in the hypoxic niches within the tumor are known to mediate resistance to several anticancer treatments and to promote cancer relapse. Thus, a careful characterization and understanding of this macrophage differentiation state is needed in order to efficiently tailor cancer therapy.

Cardiac Tissue Injury and Remodeling Is Dependent Upon MR Regulation of Activation Pathways in Cardiac Tissue Macrophages

Macrophage mineralocorticoid receptor (MR) signaling is an important mediator of cardiac tissue inflammation and fibrosis. The goal of the present study was to determine the cellular mechanisms of MR signaling in macrophages that promote cardiac tissue injury and remodeling. We sought to identify specific markers of MR signaling in isolated tissue macrophages (cardiac, aortic) vs splenic mononuclear cells from wild-type and myeloid MR-null mice given vehicle/salt or deoxycorticosterone (DOC)/salt for 8 weeks. Cardiac tissue fibrosis in response to 8 weeks of DOC/salt treatment was found in the hearts from wild-type but not myeloid MR-null mice. This was associated with an increased expression of the profibrotic markers TGF-β1 and matrix metalloproteinase-12 and type 1 inflammatory markers TNFα and chemokine (C-X-C motif) ligand-9 in cardiac macrophages. Differential expression of immunomodulatory M2-like markers (eg, arginase-1, macrophage scavenger receptor 1) was dependent on the tissue location of wild-type and MR-null macrophages. Finally, intact MR signaling is required for the phosphorylation of c-Jun NH2-terminal kinase in response to a proinflammatory stimulus in bone marrow monocytes/macrophages in culture. These data suggest that the activation of the c-Jun NH2-terminal kinase pathway in macrophages after a tissue injury and inflammatory stimuli in the DOC/salt model is MR dependent and regulates the transcription of downstream profibrotic factors, which may represent potential therapeutic targets in heart failure patients.

Liver Necrosis and Lethal Systemic Inflammation in a Murine Model of Rickettsia typhi Infection: Role of Neutrophils, Macrophages and NK Cells

Rickettsia (R.) typhi is the causative agent of endemic typhus, an emerging febrile disease that is associated with complications such as pneumonia, encephalitis and liver dysfunction. To elucidate how innate immune mechanisms contribute to defense and pathology we here analyzed R. typhi infection of CB17 SCID mice that are congenic to BALB/c mice but lack adaptive immunity. CB17 SCID mice succumbed to R. typhi infection within 21 days and showed high bacterial load in spleen, brain, lung, and liver. Most evident pathological changes in R. typhi-infected CB17 SCID mice were massive liver necrosis and splenomegaly due to the disproportionate accumulation of neutrophils and macrophages (MΦ). Both neutrophils and MΦ infiltrated the liver and harbored R. typhi. Both cell populations expressed iNOS and produced reactive oxygen species (ROS) and, thus, exhibited an inflammatory and bactericidal phenotype. Surprisingly, depletion of neutrophils completely prevented liver necrosis but neither altered bacterial load nor protected CB17 SCID mice from death. Furthermore, the absence of neutrophils had no impact on the overwhelming systemic inflammatory response in these mice. This response was predominantly driven by activated MΦ and NK cells both of which expressed IFNγ and is considered as the reason of death. Finally, we observed that iNOS expression by MΦ and neutrophils did not correlate with R. typhi uptake in vivo. Moreover, we demonstrate that MΦ hardly respond to R. typhi in vitro. These findings indicate that R. typhi enters MΦ and also neutrophils unrecognized and that activation of these cells is mediated by other mechanisms in the context of tissue damage in vivo.

Overexpression of HDAC6 induces pro-inflammatory responses by regulating ROS-MAPK-NF-κB/AP-1 signaling pathways in macrophages

Although histone deacetylase 6 (HDAC6) has been implicated in inflammatory diseases, direct involvement and its action mechanism of HDAC6 in the transcriptional regulation of pro-inflammatory genes have been unclear. In this study, we investigated the possible role of HDAC6 in the expression of pro-inflammatory mediators, indicator of macrophage activation, in RAW 264.7 cells and primary mouse macrophages. HDAC6 overexpression significantly enhanced expression of pro-inflammatory cytokines, such as TNF-α, IL-1β, and IL-6, with concomitant reduction in acetylated α-tubulin. HDAC6 overexpression significantly induced ROS generation via upregulation of NADPH oxidase expression and activity. Inhibition of ROS generation by N-acetyl cysteine, diphenyl iodonium and apocynin suppressed HDAC6-induced pro-inflammatory cytokines. An HDAC6 enzymatic inhibitor significantly inhibited ROS generation and expression of HDAC6-induced pro-inflammatory mediators, indicating the requirement of HDAC6 enzymatic activity for induction of pro-inflammatory cytokines. In addition, HDAC6 overexpression increased activation of MAPK species including ERK, JNK, and p38. Furthermore, HDAC6 overexpression resulted in activation of the NF-κB and AP-1 signaling pathways. Overall, our results provide the first evidence that HDAC6 is capable of inducing expression of pro-inflammatory genes by regulating the ROS-MAPK-NF-κB/AP-1 pathways and serves as a molecular target for inflammation.

Emerging roles of protein mannosylation in inflammation and infection

Proteins are frequently modified by complex carbohydrates (glycans) that play central roles in maintaining the structural and functional integrity of cells and tissues in humans and lower organisms. Mannose forms an essential building block of protein glycosylation, and its functional involvement as components of larger and diverse α-mannosidic glycoepitopes in important intra- and intercellular glycoimmunological processes is gaining recognition. With a focus on the mannose-rich asparagine (N-linked) glycosylation type, this review summarises the increasing volume of literature covering human and non-human protein mannosylation, including their structures, biosynthesis and spatiotemporal expression. The review also covers their known interactions with specialised host and microbial mannose-recognising C-type lectin receptors (mrCLRs) and antibodies (mrAbs) during inflammation and pathogen infection. Advances in molecular mapping technologies have recently revealed novel immuno-centric mannose-terminating truncated N-glycans, termed paucimannosylation, on human proteins. The cellular presentation of α-mannosidic glycoepitopes on N-glycoproteins appears tightly regulated; α-mannose determinants are relative rare glycoepitopes in physiological extracellular environments, but may be actively secreted or leaked from cells to transmit potent signals when required. Simultaneously, our understanding of the molecular basis on the recognition of mannosidic epitopes by mrCLRs including DC-SIGN, mannose receptor, mannose binding lectin and mrAb is rapidly advancing, together with the functional implications of these interactions in facilitating an effective immune response during physiological and pathophysiological conditions. Ultimately, deciphering these complex mannose-based receptor-ligand interactions at the detailed molecular level will significantly advance our understanding of immunological disorders and infectious diseases, promoting the development of future therapeutics to improve patient clinical outcomes.

Anti-inflammatory effects of proanthocyanidin-rich red rice extract via suppression of MAPK, AP-1 and NF-κB pathways in Raw 264.7 macrophages

BACKGROUND/OBJECTIVES

Several pharmacological properties of red rice extract have been reported including anti-oxidant, anti-tumor, and reduced cancer cell invasion. This study was conducted to evaluate the anti-inflammatory effects of red rice extract on the production of inflammatory mediators in lipopolysaccharide (LPS)-induced Raw 264.7 macrophages.

MATERIALS/METHODS

Pro-inflammatory cytokines including tumor necrosis factor-α and interleukin-6 were determined by ELISA and cyclooxygenase-2 and inducible nitric oxide synthase expression was evaluated using western blot analysis. In addition, the signaling pathway controlling the inflammatory cascade such as nuclear factor kappa B (NF-κB), activator proteins-1 (AP-1), and mitogen-activated protein kinase (MAPK) was determined.

RESULTS

Our results showed that red rice polar extract fraction (RR-P), but not non-polar extract fraction, inhibited interleukin-6, tumor necrosis factor-α, and nitric oxide production in LPS-induced Raw 264.7 cells. RR-P also reduced the expression of inflammatory enzymes, inducible nitric oxide synthase, and cyclooxygenase-2. In addition, activation of AP-1 and NF-κB transcription factor in the nucleus was abrogated by RR-P. RR-P inhibited the phosphorylation of extracellular signaling-regulated kinase 1/2, c-Jun NH2-terminal kinase, and p38 MAPK signaling responsible for the expression of inflammatory mediators in LPS-stimulated Raw 264.7 cells. Based on chemical analysis, high amounts of proanthocyanidin and catechins were detected in the RR-P fraction. However, only proanthocyanidin reduced NF-κB and AP-1 activation in LPS-activated Raw 264.7 cells.

CONCLUSION

These observations suggest that the anti-inflammatory properties of RR-P may stem from the inhibition of pro-inflammatory mediators via suppression of the AP-1, NF-κB, and MAPKs pathways.