Impaired Macrophage Function Research Articles

Phagocytic Function of Macrophages Is Impaired By Chronic Lymphocytic Leukemia and high–grade Lymphoma Progression and Can be Highly Effectively Restored for Chemo-Immunotherapy

Macrophage polarity has recently been shown to play a pivotal role in progression and prognosis of human malignancies. In CLL the high dependence of the malignant cell to the tumor microenvironment has revealed macrophages as major mediators of leukemia cell survival. In contrast, macrophage activation also offers novel therapeutic strategies for leukemia cell targeting. Here we analyze the reciprocal relationship of leukemia cells and macrophages and the specific functional impact of phagocytosis in leukemia progression and therapy.We employed the humanized hMB-Lymphoma and the Eµ-TCL1 CLL mouse model. Thioglycollate-induced macrophages, bone marrow derived murine macrophages and human monocyte derived macrophages were used for in vitroevaluation of phagocytosis either by bead based approaches or by ADCC.Applying gene-expression profiling of macrophages in Eµ-TCL1 mice we could identify profound transcriptional alterations indicating a re-programming during leukemogenesis. Functional genomic analysis particularly revealed impaired phagocytic function induced during leukemia onset. In vivo and ex vivo phagocytosis assays of primary macrophages showed a significant reduced phagocytic activity during CLL progression. Human macrophages in co-culture with CLL cells in vitro compared to healthy B-cells similarly showed defects in phagocytosis. In the humanized leukemia model we similarly observed impaired phagocytosis resulting in resistance towards therapeutic antibody/macrophage mediated therapy. Resistance was actively induced by increasing leukemia cell infiltration in the bone marrow. Impaired macrophage function could be identified being mediated by secretory crosstalk such as release of PGE2 by leukemia cells and Cholecalciferol. We could restore phagocytic function by combination regimens involving therapeutic antibodies and chemotherapy. Specifically, an acute secretory activating phenotype (ASAP), releasing cytokines from leukemia cells induces macrophage infiltration and phagocytic activity in the bone marrow. Thus, malignant cells can be effectively targeted by modulation of macrophage polarization and function.In conclusion, we have identified decreased phagocytic activity of macrophages as key functional aspect in leukemia and lymphoma associated macrophages. Inversely, enhancing phagocytosis rendered essential for the re-sensitization of refractory niches treatment towards monoclonal antibodies defined by macrophage polarity. Overall macrophage function represents a key therapeutic target in CLL and other B-cell malignancies. DisclosuresNo relevant conflicts of interest to declare.

Heme oxygenase-2 deletion impairs macrophage function: implication in wound healing.

Heme oxygenase (HO)-2 deficiency impairs wound healing and exacerbates inflammation following injury. We examine the impact of HO-2 deficiency on macrophage function and the contribution of macrophage HO-2 to inflammatory and repair responses to injury. Corneal epithelial debridement was performed in control and macrophage-depleted HO-2(-/-) and wild-type (WT) mice and in bone marrow chimeras. Peritoneal macrophages were collected for determination of phagocytic activity and classically activated macrophage (M1)-alternatively activated macrophage (M2) polarization. Depletion of macrophages delayed corneal healing (13.2%) and increased neutrophil infiltration (54.1%) by day 4 in WT mice, whereas in HO-2(-/-) mice, it did not worsen the already impaired wound healing and exacerbated inflammation. HO-2(-/-) macrophages displayed an altered M1 phenotype with no significant expression of M2 or M2-like activated cells and a 31.3% reduction in phagocytic capacity that was restored by inducing HO-1 activity or supplementing biliverdin. Macrophage depletion had no effect, whereas adoptive transfer of WT bone marrow improved wound healing (34% on day 4) but did not resolve the exaggerated inflammatory response in HO-2(-/-) mice. These findings indicate that HO-2-deficient macrophages are dysfunctional and that macrophage HO-2 is required for proper macrophage function but is insufficient to correct the impaired healing of the HO-2(-/-) cornea, suggesting that corneal epithelial expression of HO-2 is a key to resolution and repair in wound healing.

Maresin-like Lipid Mediators Are Produced by Leukocytes and Platelets and Rescue Reparative Function of Diabetes-Impaired Macrophages

Nonhealing diabetic wounds are associated with impaired macrophage (Mf) function. Leukocytes and platelets (PLT) play crucial roles in wound healing by poorly understood mechanisms. Here we report the identification and characterization of the maresin-like(L) mediators 14,22-dihydroxy-docosa-4Z,7Z,10Z,12E,16Z,19Z-hexaenoic acids, 14S,22-diHDHA (maresin-L1), and 14R,22-diHDHA (maresin-L2) that are produced by leukocytes and PLT and involved in wound healing. We show that 12-lipoxygenase-initiated 14S-hydroxylation or cytochrome P450 catalyzed 14R-hydroxylation and P450-initiated ω(22)-hydroxylation are required for maresin-L biosynthesis. Maresin-L treatment restores reparative functions of diabetic Mfs, suggesting that maresin-Ls act as autocrine/paracrine factors responsible for, at least in part, the reparative functions of leukocytes and PLT in wounds. Additionally, maresin-L ameliorates Mf inflammatory activation and has the potential to suppress the chronic inflammation in diabetic wounds caused by activation of Mfs. These findings provide initial insights into maresin-L biosynthesis and mechanism of action and potentially offer a therapeutic option for better treatment of diabetic wounds.

Dietary glutamine supplementation partly reverses impaired macrophage function resulting from overload training in rats.

The aim of this study was to evaluate the effect of overload training on the function of peritoneal macrophages in rats, and to test the hypothesis that glutamine in vivo supplementation would partly reverse the eventual functional alterations induced by overload training in these cells. Forty male Wistar rats were randomly divided into 5 groups: control group (C), overload training group (E1), overload training and restore one week group (E2), glutamine-supplementation group (EG1), and glutamine-supplementation and restore 1-week group (EG2). All rats, except those placed on sedentary control were subjected to 11 weeks of overload training protocol. Blood hemoglobin, serum testosterone, and corticosterone of rats were measured. Moreover, the functions (chemotaxis, phagocytosis, cytokines synthesis, reactive oxygen species generation) of peritoneal macrophages were determined. Data showed that blood hemoglobin, serum testosterone, corticosterone and body weight in the overload training group decreased significantly as compared with the control group. Meanwhile, the chemotaxis capacity (decreased by 31%, p = .003), the phagocytosis capacity (decreased by 27%, p = .005), the reactive oxygen species (ROS) generation (decreased by 35%, p = .003) and the cytokines response capability of macrophages were inhibited by overload training. However, the hindering of phagocytosis and the cytokines response capability of macrophages induced by overload training could be ameliorated and reversed respectively, by dietary glutamine supplementation. These results suggest that overload training impairs the function of peritoneal macrophages, which is essential for the microbicidal actions of macrophages. This may represent a novel mechanism of immunodepression induced by overload training. Nonetheless, dietary glutamine supplementation could partly reverse the impaired macrophage function resulting from overload training.

Transient Receptor Potential Ion Channels

This article reviews the current understanding of transient receptor potential ion channels (TRP channels) in health and disease. Transient receptor potential ion channels are a group of 27 channels that are expressed in all tissues. These channels play important roles in surgically important problems, such as chronic pain, susceptibility to infection, hypothermia, and some cancers. A literature search was performed. This review focuses on the role of TRP channels in a few surgically important disease processes, such as pain, inflammation, airway diseases, and malignant melanomas. In addition, we discuss some of the structural properties that are important for the activation of TRP channels. TRPA1 and TRPV1 are expressed on pain fibers and play an important role in the development of chronic pain, such as chemotherapy-related neuropathic pain. Deletion of TRPA1 and TRPV1 suppresses the development of chronic pain, and blockers of TRPA1 and TRPV1 show promise as a new class of painkillers. Furthermore, several TRP channels are expressed on immune cells. Macrophages express at least 3 different TRP channels, and the properly balanced activation of all these channels together allows normal macrophage function. Deletion of any of these channels results in impaired macrophage function and increased susceptibility to infection. Because several of these TRP channels on macrophages are temperature sensitive, they may comprise the link for hypothermia-related infectious complications in trauma, and to a lesser degree, in elective surgical patients. Transient receptor potential ion channels are involved in several surgically important disease processes. Activation or blockade of these channels offers new therapeutic opportunities. Pharmacologic activation or blockade of TRP channels may offer new treatment options in surgical patients for the management of pain and infections.

Studies in primary and iPSC-derived human Gaucher macrophages demonstrate impaired macrophage function and defective autophagy

computerized tomography (HRCT) mainly in type I GD adults. So, this study will determine the clinical spectrum of severity of lung involvement in Egyptian children mainly type 3 GD, the radiological changes,assess clinical significance of these findings and their response to ERT. The study included 34 GD children diagnosed by enzyme assay and genotype and are on ERT, imiglucerase 30-60 IU/kg/2 weeks. 31 GD type 3 children (29L444P/L444P, 2 D409H/D409H) and 3 GD type I (1 R359Q/R359Q and 2 with unknown genotype) were followed over 7 years. Their pulmonary status was clinically and radiologically assessed by chest x-ray and HRCT and its response to ERT determined. Clinical variables and radiological findings were statistically correlated. Patients’ median age is 8.6 years and mean duration of ERT is 6.5 years. Twenty (59%) type 3 L4444P/L444P GD children, 13 males and 7 females had chest symptoms with 14 having recurrent chest infections, dyspnea and wheezing, 4 requiring intensive care admission and 1 died of severe pulmonary involvement. Children showed statistically significant higher prevalence of chest symptoms at younger age (p= 0.04). The chest xray and HRCT findings included coarse interstitial pulmonary thickening of variable severity in 26/34(76.5%) and in 90% of the symptomatic group. Other changes included bronchiectasis, gound glass veiling, hyperinflation, mediastinal lymphadenopathy, military infiltration, consolidation, atelectasis and air trapping. In 12/14 asymptomatic GD children findings varied from interstitial thickening to ground glass veiling and bronchiectactic changes. 3 children were splenectomised without worsening of their chest condition. In 13 symptomatic children there was dramatic clinical response to ERT but radiological findings were stationary. All L444P/L444P children showed moderate to severe neurological involvement, 4 had epilepsy, 8 mesenteric lymphadenopathy, 3 severe bone involvement, 2 severe skeletal deformities, aortic and mitral calcifications in D409H/D409H patients. Nearly all children with recurrent infections and significant chest findings have at least one other severe system involvement. Our study showed heterogeneity in clinical presentation and response of lung involvement to ERT in type 3 GD children. 76.5% had variable degrees of interstitial lung disease and nearly all children without clinical lung involvement had abnormal radiological findings. Chest symptoms showed improvement in 65%. Lung involvement can be among the determinants of severity of type 3 GD in children.

Transcription Profiling Reveals Potential Mechanisms of Dysbiosis in the Oral Microbiome of Rhesus Macaques with Chronic Untreated SIV Infection

A majority of individuals infected with human immunodeficiency virus (HIV) have inadequate access to antiretroviral therapy and ultimately develop debilitating oral infections that often correlate with disease progression. Due to the impracticalities of conducting host-microbe systems-based studies in HIV infected patients, we have evaluated the potential of simian immunodeficiency virus (SIV) infected rhesus macaques to serve as a non-human primate model for oral manifestations of HIV disease. We present the first description of the rhesus macaque oral microbiota and show that a mixture of human commensal bacteria and “macaque versions” of human commensals colonize the tongue dorsum and dental plaque. Our findings indicate that SIV infection results in chronic activation of antiviral and inflammatory responses in the tongue mucosa that may collectively lead to repression of epithelial development and impact the microbiome. In addition, we show that dysbiosis of the lingual microbiome in SIV infection is characterized by outgrowth of Gemella morbillorum that may result from impaired macrophage function. Finally, we provide evidence that the increased capacity of opportunistic pathogens (e.g. E. coli) to colonize the microbiome is associated with reduced production of antimicrobial peptides.

Low Levels of Insulin-like Growth Factor-1 Contribute to Alveolar Macrophage Dysfunction in Cystic Fibrosis

Alveolar macrophages are major contributors to lung innate immunity. Although alveolar macrophages from cystic fibrosis (CF) transmembrane conductance regulator(-/-) mice have impaired function, no study has investigated primary alveolar macrophages in adults with CF. CF patients have low levels of insulin-like growth factor 1 (IGF-1), and our prior studies demonstrate a relationship between IGF-1 and macrophage function. We hypothesize that reduced IGF-1 in CF leads to impaired alveolar macrophage function and chronic infections. Serum and bronchoalveolar lavage (BAL) samples were obtained from eight CF subjects and eight healthy subjects. Macrophages were isolated from BAL fluid. We measured the ability of alveolar macrophages to kill Pseudomonas aeruginosa. Subsequently, macrophages were incubated with IGF-1 prior to inoculation with bacteria to determine the effect of IGF-1 on bacterial killing. We found a significant decrease in bacterial killing by CF alveolar macrophages compared with control subjects. CF subjects had lower serum and BAL IGF-1 levels compared with healthy control subjects. Exposure to IGF-1 enhanced alveolar macrophage macrophages in both groups. Finally, exposing healthy alveolar macrophages to CF BAL fluid decreased bacterial killing, and this was reversed by the addition of IGF-1, whereas IGF-1 blockade worsened bacterial killing. Our studies demonstrate that alveolar macrophage function is impaired in patients with CF. Reductions in IGF-1 levels in CF contribute to the impaired alveolar macrophage function. Exposure to IGF-1 ex vivo results in improved function of CF alveolar macrophages. Further studies are needed to determine whether alveolar macrophage function can be enhanced in vivo with IGF-1 treatment.

Chronic Alcohol Induces M2 Polarization Enhancing Pulmonary Disease Caused by Exposure to Particulate Air Pollution

Chronic alcohol consumption causes persistent oxidative stress in the lung, leading to impaired alveolar macrophage (AM) function and impaired immune responses. AMs play a critical role in protecting the lung from particulate matter (PM) inhalation by removing particulates from the airway and secreting factors which mediate airway repair. We hypothesized AM dysfunction caused by chronic alcohol consumption increases the severity of injury caused by PM inhalation. Age- and sex-matched C57BL/6 mice were fed the Lieber-DeCarli liquid diet containing either alcohol or an isocaloric substitution (control diet) for 8weeks. Mice from both diet groups were exposed to combustion-derived PM (CDPM) for the final 2weeks. AM number, maturation, and polarization status were assessed by flow cytometry. Noninvasive and invasive strategies were used to assess pulmonary function and correlated with histomorphological assessments of airway structure and matrix deposition. Co-exposure to alcohol and CDPM decreased AM number and maturation status (CD11c expression), while increasing markers of M2 activation (interleukin [IL]-4Rα, Ym1, Fizz1 expression, and IL-10 and transforming growth factor [TGF]-β production). Changes in AM function were accompanied by decreased airway compliance and increased elastance. Altered lung function was attributable to elevated collagen content localized to the small airways and loss of alveolar integrity. Intranasal administration of neutralizing antibody to TGF-β during the CDPM exposure period improved changes in airway compliance and elastance, while reducing collagen content caused by co-exposure. Combustion-derived PM inhalation causes enhanced disease severity in the alcoholic lung by stimulating the release of latent TGF-β stores in AMs. The combinatorial effect of elevated TGF-β, M2 polarization of AMs, and increased oxidative stress impairs pulmonary function by increasing airway collagen content and compromising alveolar integrity.

New Aspects on Human Rhinovirus Infections

New Aspects on Human Rhinovirus Infections

Biochemical index and immunological function in the peripheral blood of patients with idiopathic pulmonary alveolar proteinosis

Idiopathic pulmonary alveolar proteinosis (PAP) has recently been recognized as a disease of impaired alveolar macrophage function caused by the neutralizing granulocyte-macrophage colony stimulating factor (GM-CSF) autoantibody. However, the change of immunological function and biochemical index in the peripheral blood of patients with idiopathic PAP remains unclear. The clinical data of 29 patients with idiopathic PAP and 30 normal subjects were retrospectively analyzed. Biochemical indices, immunoglobulin and complement of all participants, and immunocytes in 19 patients and 30 normal subjects were evaluated. The peripheral blood of the patients showed a decrease in CD4+/CD8+ (P<0.05) and the percentage of the CD4+ T lymphocyte and helper T lymphocyte (both P<0.01), whereas an increase was observed in the percentage of the suppressor T lymphocyte (P<0.01) compared to the normal subjects. No significant differences were found in the concentration of IgG, IgA, IgM, C3 and C4 between the two groups. An increase was observed in LDH (P<0.01) and cytokeratin fragment antigen (CYFR) 211 (P<0.01) in the peripheral blood of the patients compared to that of normal subjects. The serum level of LDH was negatively correlated with FVC% Pred (P<0.05), DLCO% Pred (P<0.05), PaO2 (P<0.05) and positively associated with the dyspnea score (P<0.05) of 29 patients, and positively correlated with the score of high-resolution computed tomography (HRCT) of the chest of 21 patients (P<0.05). The serum level of CYFR211 was negatively correlated with DLCO% Pred (P<0.05) and positively associated with the dyspnea score (P<0.05). Findings of the present study suggest that hypofunction of cellular immunity may exist in the patients with idiopathic PAP. LDH and CYFRA211 may be considered as important indices to monitor the severity of idiopathic PAP.

Acute ethanol administration inhibits Toll-like receptor 4 signaling pathway in rat intestinal epithelia

Excess alcohol intake, as in binge drinking, increases susceptibility to microbial pathogens. Alcohol impairs macrophage function by suppression of the Toll-like receptor 4 (TLR4) pathway. This study investigated the effects of acute ethanol intake on the TLR4 pathway in rat intestinal epithelia, which usually encounters luminal antigens at first and participates in the development of intestinal immunity. Twenty Wistar rats were randomly assigned to an ethanol group given ethanol as a 25% (v/v) solution in water at 7.5 g/kg, or a control group given saline, by oral gavage daily for 3 days. The epithelial histology and ultrastructure, the intestinal microflora, peripheral and portal venous plasma lipopolysaccharide (LPS) levels, and somatostatin (SST) levels in the peripheral plasma and small intestine were evaluated. Somatostatin receptor 2 (SSTR2), TLR4, TANK binding kinase-1 (TBK1), activated nuclear factor-κB (NF-κB), interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) in the intestinal mucosa were assayed. LPS responsiveness with or without SST pretreatment was assayed in vitro by quantification of TLR4, TBK1, activated NF-κB, IFN-γ and TNF-α in isolated intestinal epithelia. Mucosal damage was observed in the ethanol group by light and electron microscopy. Escherichia coli cultures were unchanged in rat intestine of the ethanol group compared with controls, but lactobacilli cultures were reduced (p < 0.05). LPS levels increased in peripheral and portal venous plasma (p < 0.05), but mucosal TLR4, TBK1, nuclear NF-κB, IFN-γ and TNF-α were unchanged in the ethanol group. LPS treatment in vitro up-regulated the level of TLR4, TBK1 and nuclear NF-κB as well as the production of IFN-γ and TNF-α in isolated intestinal epithelia in the control (p < 0.05), but not the ethanol group. The stimulatory effects of LPS on intestinal epithelia isolated from the control group were significantly inhibited by SST pretreatment (p < 0.05). The peripheral plasma and intestinal levels of SST and the mucosal expression of SSTR2 in the ethanol group were significantly higher than in the control group (p < 0.05). These findings suggest the hyposensitivity of intestinal epithelial TLR4 to LPS induced by acute alcohol abuse probably through ethanol per se and ethanol-enhanced intestinal mucosal SST pathway may be a novel mechanism for increased susceptibility to intestinal pathogens.

Donor and Recipient Cell Surface Colony Stimulating Factor-1 Promote Neointimal Formation in Transplant-Associated Arteriosclerosis

Transplant-associated arteriosclerosis manifests as progressive vascular neointimal expansion throughout the arterial system of allografted solid organs, and eventually compromises graft perfusion and function. Allografts placed in colony stimulating factor (CSF)-1-deficient osteopetrotic (Csf1(op)/Csf1(op)) mice develop very little neointima, a finding attributed to impaired recipient macrophage function. We examined how CSF-1 affects neointima-derived vascular smooth muscle cells, tested the significance of CSF-1 expressed in donor tissue, and evaluated the contribution of secreted versus cell surface CSF-1 isoforms in transplant-associated arteriosclerosis. CSF-1 activated specific signaling pathways to promote migration, survival, and proliferation of cultured vascular smooth muscle cells. Tumor necrosis factor-α addition increased CSF-1 and CSF-1 receptor expression, and tumor necrosis factor-α-driven proliferation was blocked by anti-CSF-1 antibody. In a mouse vascular allograft model, lack of recipient or donor CSF-1 impaired neointima formation; the latter suggests local CSF-1 function within the allograft. Moreover, reconstitution of donor or recipient cell surface CSF-1, without secreted CSF-1, restored neointimal formation. Vascular smooth muscle cells activation, including that mediated by tumor necrosis factor-α, can be driven in an autocrine/juxtacrine manner by CSF-1. These studies provide evidence for local function of CSF-1 in neointimal expansion, and identify CSF-1 signaling in vascular smooth muscle cells, particularly cell surface CSF-1 signaling, as a target for therapeutic strategies in transplant-associated arteriosclerosis.

Human Amnion Epithelial Cells do Not Abrogate Pulmonary Fibrosis in Mice with Impaired Macrophage Function

Since current treatments for both acute and chronic lung diseases are less than ideal, there has been recent interest in the use of cell-based therapies for inflammatory lung disease. Specifically, human amnion epithelial cells (hAECs) have been shown to reduce bleomycin-induced lung injury and prevent subsequent loss of respiratory function, primarily through modulation of the host immune response. The precise mechanisms of this effect remain unclear. We aimed to investigate the potential of hAECs to mitigate bleomycin-induced lung injury in surfactant protein C deficient (Sftpc(−/−)) mice, which are highly susceptible to pulmonary injury as a result of impairment of macrophage function. Primary hAECs were administered to wild-type (Sftpc(+/+)) and Sftpc(−/−) mice 24 h after exposure to bleomycin. Compared to Sftpc(+/+) mice receiving bleomycin alone, Sftpc(+/+) mice administered hAECs 24 h after bleomycin exposure had decreased expression of proinflammatory genes, decreased macrophage and neutrophil infiltration, fibrosis, collagen content, and α-smooth muscle actin as well as a significant improvement in lung function. Compared to Sftpc(−/−) mice given bleomycin alone, Sftpc(−/−) mice administered hAECs 24 h after bleomycin did not have a decrease in inflammatory gene expression or a reduction in macrophage pulmonary infiltration. Subsequently, Sftpc(−/−) mice did not show any decrease in pulmonary fibrosis or improvement of lung function after hAEC administration. The ability of hAECs to mitigate bleomycin-induced lung injury is abolished in Sftpc(−/−) mice, suggesting that hAECs require normal host macrophage function to exert their reparative effects.

Ethanol (EtOH)‐Induced TGF‐β1 and Reactive Oxygen Species Production Are Necessary for EtOH‐Induced Alveolar Macrophage Dysfunction and Induction of Alternative Activation

Previous studies have shown that chronic ethanol (EtOH) ingestion results in impaired alveolar macrophage function, increased TGF-β(1) production, and decreased antioxidant availability. Similarly, alternative activation (M2 activation) of alveolar macrophages also induces TGF-β(1) production and impairs macrophage function. However, the potential links between EtOH-induced alveolar macrophage derangements, M2 activation, TGF-β(1) production signaling, and oxidant stress have yet to be examined. We hypothesized that EtOH-induced oxidant stress and induction of TGF-β(1) signaling result in alternative activation which subsequently impairs the phagocytic capacity of alveolar macrophages. Primary rat alveolar macrophages and the alveolar macrophages cell line NR8383 were treated with 0.08% EtOH±the antioxidant glutathione (GSH) or a TGF-β(1) neutralizing antibody for 5days. Outcome measures included TGF-β(1) production, reactive oxygen species (ROS) production, phagocytic capacity, and expression of markers of M2 activation. Chronic EtOH treatment greatly decreased alveolar macrophage phagocytic function, increased ROS production, increased TGF-β(1) , and increased expression of markers of M2 activation. GSH supplementation and inhibition of TGF-β(1) signaling during EtOH treatment prevented these alterations. EtOH treatment increased oxidant stress, TGF-β(1) production, and alternative activation in NR8383 cells. However, GSH supplementation and ablation of TGF-β(1) signaling prevented these effects. This suggested that the EtOH-induced switch to an M2 phenotype was a result of decreased antioxidant availability and increased TGF-β(1) signaling. Preventing EtOH-induced induction of alternative activation may improve alveolar macrophage function in alcoholic subjects and decrease the risk of respiratory infections.

Ethanol Induces Oxidative Stress in Alveolar Macrophages via Upregulation of NADPH Oxidases

Chronic alcohol abuse is a comorbid variable of acute respiratory distress syndrome. Previous studies showed that, in the lung, chronic alcohol consumption increased oxidative stress and impaired alveolar macrophage (AM) function. NADPH oxidases (Noxes) are the main source of reactive oxygen species in AMs. Therefore, we hypothesized that chronic alcohol consumption increases AM oxidant stress through modulation of Nox1, Nox2, and Nox4 expression. AMs were isolated from male C57BL/6J mice, aged 8-10 wk, which were treated with or without ethanol in drinking water (20% w/v, 12 wk). MH-S cells, a mouse AM cell line, were treated with or without ethanol (0.08%, 3 d) for in vitro studies. Selected cells were treated with apocynin (300 μM), a Nox1 and Nox2 complex formation inhibitor, or were transfected with Nox small interfering RNAs (20-35 nM), before ethanol exposure. Human AMs were isolated from alcoholic and control patients' bronchoalveolar lavage fluid. Nox mRNA levels (quantitative RT-PCR), protein levels (Western blot and immunostaining), oxidative stress (2',7'-dichlorofluorescein-diacetate and Amplex Red analysis), and phagocytosis (Staphylococcus aureus internalization) were measured. Chronic alcohol increased Nox expression and oxidative stress in mouse AMs in vivo and in vitro. Experiments using apocynin and Nox small interfering RNAs demonstrated that ethanol-induced Nox4 expression, oxidative stress, and AM dysfunction were modulated through Nox1 and Nox2 upregulation. Further, Nox1, Nox2, and Nox4 protein levels were augmented in human AMs from alcoholic patients compared with control subjects. Ethanol induces AM oxidative stress initially through upregulation of Nox1 and Nox2 with downstream Nox4 upregulation and subsequent impairment of AM function.

Acute alcohol exposure impairs macrophage function on clearance of apoptotic cells via inhibition of MFG‐E8 gene expression through a H2O2 dependent mechanism

Alcohol is found to inhibit macrophage (MΦ) function on clearance of apoptotic cells. Milk fat globule‐EGF factor 8 (MFG‐E8) is an important molecule for MΦ to identify apoptotic cells. We hypothesized that alcohol impacts MΦ function on clearance of apoptotic cells through alteration of MFG‐E8 levels in MΦ. To this end, we treated mouse MΦ with alcohol (25 mM) for 18 h and processed the cells for determining MFG‐E8 expression, activity of MFG‐E8 gene promoter, and ability of the cells to clearance of apoptotic cells. We found that acute alcohol exposure resulted in repression of MΦ activity on clearance of apoptotic cells. This effect was associated with down‐regulation of MFG‐E8 gene expression as well as reduction of its promoter activity. Recombinant MFG‐E8 (10 nM) rescued alcohol‐treated MΦ from clearance of apoptotic cells, suggesting that down‐regulation of MFG‐E8 contributes to alcohol effect on impairment of MΦ functions on clearance of apoptotic cells. In addition, we revealed that H2O2 mimics alcohol effect on MFG‐E8 gene expression and phagocytosis of apoptotic cells. Antioxidant NAC (10mM) attenuated the alcohol action. Collectively, our data suggest that acute alcohol exposure impairs macrophage function on clearance of apoptotic cells via inhibition of MFG‐E8 gene expression through a H2O2 dependent mechanism. This effect may play an important role in pathogenesis of alcohol‐induced tissue injury. (Supported by NIH R21AA020494 &amp; R01DK064240).

Recruitment of monocytes/macrophages by tissue factor-mediated coagulation is essential for metastatic cell survival and premetastatic niche establishment in mice

AbstractTissue factor (TF) expression by tumor cells correlates with metastasis clinically and supports metastasis in experimental settings. However, the precise pathways coupling TF to malignancy remain incompletely defined. Here, we show that clot formation by TF indirectly enhances tumor cell survival after arrest in the lung, during experimental lung metastasis, by recruiting macrophages characterized by CD11b, CD68, F4/80, and CX3CR1 (but not CD11c) expression. Genetic or pharmacologic inhibition of coagulation, by either induction of TF pathway inhibitor ex-pression or by treatment with hirudin, respectively, abrogated macrophage recruitment and tumor cell survival. Furthermore, impairment of macrophage function, in either Mac1-deficient mice or in CD11b-diphtheria toxin receptor mice in which CD11b-positive cells were ablated, decreased tumor cell survival without altering clot formation, demonstrating that the recruitment of functional macrophages was essential for tumor cell survival. This effect was independent of NK cells. Moreover, a similar population of macrophages was also recruited to the lung during the formation of a premetastatic niche. Anticoagulation inhibited their accumulation and prevented the enhanced metastasis associated with the formation of the niche. Our study, for the first time, links TF induced coagulation to macrophage recruitment in the metastatic process.

Unloading stress disturbs muscle regeneration through perturbed recruitment and function of macrophages

Skeletal muscle is one of the most sensitive tissues to mechanical loading, and unloading inhibits the regeneration potential of skeletal muscle after injury. This study was designed to elucidate the specific effects of unloading stress on the function of immunocytes during muscle regeneration after injury. We examined immunocyte infiltration and muscle regeneration in cardiotoxin (CTX)-injected soleus muscles of tail-suspended (TS) mice. In CTX-injected TS mice, the cross-sectional area of regenerating myofibers was smaller than that of weight-bearing (WB) mice, indicating that unloading delays muscle regeneration following CTX-induced skeletal muscle damage. Delayed infiltration of macrophages into the injured skeletal muscle was observed in CTX-injected TS mice. Neutrophils and macrophages in CTX-injected TS muscle were presented over a longer period at the injury sites compared with those in CTX-injected WB muscle. Disturbance of activation and differentiation of satellite cells was also observed in CTX-injected TS mice. Further analysis showed that the macrophages in soleus muscles were mainly Ly-6C-positive proinflammatory macrophages, with high expression of tumor necrosis factor-α and interleukin-1β, indicating that unloading causes preferential accumulation and persistence of proinflammatory macrophages in the injured muscle. The phagocytic and myotube formation properties of macrophages from CTX-injected TS skeletal muscle were suppressed compared with those from CTX-injected WB skeletal muscle. We concluded that the disturbed muscle regeneration under unloading is due to impaired macrophage function, inhibition of satellite cell activation, and their cooperation.

Pulmonary alveolar proteinosis and superinfection with pulmonary tuberculosis in a case

Pulmonary alveolar proteinosis (PAP) is a rare and diffuse lung process, characterized by the presence of alveolar spaces filled with amorphous eosinophilic material. Impaired macrophage function and impaired host defence due to abnormalities of surfactant proteins may favor the growth of microorganisms. The association of alveolar proteinosis with mycobacterial infections is rarely reported. The PAP and superinfection with pulmonary tuberculosis is defined by radiologic and histopathologic in a 46 year-old patient. The patients with PAP should be monitored for superinfection. It may cause the disease progression and radiological, clinical symptoms may improve with treatment of superinfection.