CD163 and its expanding functional repertoire

COPD Patients Exhibit Distinct Gene Expression, Accelerated Cellular Aging, and Bias to M2 Macrophages

COPD, one of world's leading contributors to morbidity and mortality, is characterized by airflow limitation and heterogeneous clinical features. Three main phenotypes are proposed: overlapping asthma/COPD (ACO), exacerbator, and emphysema. Disease severity can be classified as mild, moderate, severe, and very severe. The molecular basis of inflammatory amplification, cellular aging, and immune response are critical to COPD pathogenesis. Our aim was to investigate EP300 (histone acetylase, HAT), HDAC 2 (histone deacetylase), HDAC3, and HDAC4 gene expression, telomere length, and differentiation ability to M1/M2 macrophages. For this investigation, 105 COPD patients, 42 smokers, and 73 non-smoker controls were evaluated. We identified a reduced HDAC2 expression in patients with mild, moderate, and severe severity; a reduced HDAC3 expression in patients with moderate and severe severity; an increased HDAC4 expression in patients with mild severity; and a reduced EP300 expression in patients with severe severity. Additionally, HDAC2 expression was reduced in patients with emphysema and exacerbator, along with a reduced HDAC3 expression in patients with emphysema. Surprisingly, smokers and all COPD patients showed telomere shortening. COPD patients showed a higher tendency toward M2 markers. Our data implicate genetic changes in COPD phenotypes and severity, in addition to M2 prevalence, that might influence future treatments and personalized therapies.

Candidate SNP Markers Significantly Altering the Affinity of TATA-Binding Protein for the Promoters of Human Hub Genes for Atherogenesis, Atherosclerosis and Atheroprotection

Atherosclerosis is a systemic disease in which focal lesions in arteries promote the build-up of lipoproteins and cholesterol they are transporting. The development of atheroma (atherogenesis) narrows blood vessels, reduces the blood supply and leads to cardiovascular diseases. According to the World Health Organization (WHO), cardiovascular diseases are the leading cause of death, which has been especially boosted since the COVID-19 pandemic. There is a variety of contributors to atherosclerosis, including lifestyle factors and genetic predisposition. Antioxidant diets and recreational exercises act as atheroprotectors and can retard atherogenesis. The search for molecular markers of atherogenesis and atheroprotection for predictive, preventive and personalized medicine appears to be the most promising direction for the study of atherosclerosis. In this work, we have analyzed 1068 human genes associated with atherogenesis, atherosclerosis and atheroprotection. The hub genes regulating these processes have been found to be the most ancient. In silico analysis of all 5112 SNPs in their promoters has revealed 330 candidate SNP markers, which statistically significantly change the affinity of the TATA-binding protein (TBP) for these promoters. These molecular markers have made us confident that natural selection acts against underexpression of the hub genes for atherogenesis, atherosclerosis and atheroprotection. At the same time, upregulation of the one for atheroprotection promotes human health.

Multifaceted Roles of CD5L in Infectious and Sterile Inflammation

CD5L, a protein expressed and secreted mainly by macrophages, is emerging as a critical immune effector. In addition to its well-defined function as an anti-apoptotic protein, research over the last decade has uncovered additional roles that range from pattern recognition to autophagy, cell polarization, and the regulation of lipid metabolism. By modulating all these processes, CD5L plays a key role in highly prevalent diseases that develop by either acute or chronic inflammation, including several infectious, metabolic, and autoimmune conditions. In this review, we summarize the current knowledge of CD5L and focus on the relevance of this protein during infection- and sterile-driven inflammatory pathogenesis, highlighting its divergent roles in the modulation of inflammation.

TREM2 suppresses the proinflammatory response to facilitate PRRSV infection via PI3K/NF-κB signaling

Triggering receptor expressed on myeloid cells 2 (TREM2) serves as an anti-inflammatory receptor, negatively regulating the innate immune response. TREM2 is mainly expressed on dendritic cells and macrophages, the target cells of porcine reproductive and respiratory syndrome virus (PRRSV). Thus, we investigated the potential role of TREM2 in PRRSV infection in porcine alveolar macrophages (PAMs). We found that there was an increased expression of TREM2 upon PRRSV infection in vitro. TREM2 silencing restrained the replication of PRRSV, whereas TREM2 overexpression facilitated viral replication. The cytoplasmic tail domain of TREM2 interacted with PRRSV Nsp2 to promote infection. TREM2 downregulation led to early activation of PI3K/NF-κB signaling, thus reinforcing the expression of proinflammatory cytokines and type I interferons. Due to the enhanced cytokine expression, a disintegrin and metalloproteinase 17 was activated to promote the cleavage of membrane CD163, which resulted in suppression of infection. Furthermore, exogenous soluble TREM2 (sTREM2)-mediated inhibition of PRRSV attachment might be attributed to its competitive binding to viral envelope proteins. In pigs, following PRRSV challenge in vivo, the expression of TREM2 in lungs and lymph nodes as well as the production of sTREM2 were significantly increased. These novel findings indicate that TREM2 plays a role in regulating PRRSV replication via the inflammatory response. Therefore, our work describes a novel antiviral mechanism against PRRSV infection and suggests that targeting TREM2 could be a new approach in the control of the PRRSV infection.

Characterization of Antigen-Presenting Cell Subsets in Human Liver-Draining Lymph Nodes

T-cell immunity in the liver is tightly regulated to prevent chronic liver inflammation in response to antigens and toxins derived from food and intestinal bacterial flora. Since the main sites of T cell activation in response to foreign components entering solid tissues are the draining lymph nodes (LN), we aimed to study whether Antigen-Presenting Cell (APC) subsets in human liver lymph-draining LN show features that may contribute to the immunologically tolerant liver environment. Healthy liver LN, iliac LN, spleen and liver perfusates were obtained from multi-organ donors, while diseased liver LN were collected from explanted patient livers. Inguinal LN were obtained from kidney transplant recipients. Mononuclear cells were isolated from fresh tissues, and immunophenotypic and functional characteristics of APC subsets were studied using flowcytometry and in ex vivo cultures. Healthy liver-draining LN contained significantly lower relative numbers of CD1c⁺ conventional dendritic cells (cDC2), plasmacytoid DC (PDC), and CD14⁺CD163⁺DC-SIGN⁺ macrophages (MF) compared to inguinal LN. Compared to spleen, both types of LN contained low relative numbers of CD141^hi cDC1. Both cDC subsets in liver LN showed a more activated/mature immunophenotype than those in inguinal LN, iliacal LN, spleen and liver tissue. Despite their more mature status, cDC2 isolated from hepatic LN displayed similar cytokine production capacity (IL-10, IL-12, and IL-6) and allogeneic T cell stimulatory capacity as their counterparts from spleen. Liver LN from patients with inflammatory liver diseases showed a further reduction of cDC1, but had increased relative numbers of PDC and MF. In steady state conditions human liver LN contain relatively low numbers of cDC2, PDC, and macrophages, and relative numbers of cDC1 in liver LN decline during liver inflammation. The paucity of cDC in liver LN may contribute to immune tolerance in the liver environment.

Effect of metabolic status on conceptus-maternal interactions on day 19 in dairy cattle: II. Effects on the endometrial transcriptome

The aim of this study was to test the hypothesis that the metabolic stresses associated with lactation alter the ability of the endometrium to respond appropriately to the conceptus by examining endometrial gene expression on day 19 of pregnancy. Immediately after calving, primiparous Holstein cows with similar production and fertility estimated breeding values were randomly divided into two groups and either dried off (i.e. never milked) immediately or milked twice daily. Approximately 65-75 days postpartum, grade 1 blastocysts recovered from superovulated Holstein heifer donors (n = 5) were transferred (1 per recipient) into lactating (n = 11) and nonlactating (n = 11) recipients. Control nulliparous Holstein heifers (n = 6) were artificially inseminated. RNA-sequencing was performed on intercaruncular endometrial samples recovered at slaughter from confirmed pregnant animals on day 19 (n = 5 lactating and nonlactating cows; n = 4 heifers). Differentially expressed genes (DEGs) were identified between both postpartum groups compared to heifers and between lactating and nonlactating cows. Functional annotation of DEGs between cows and heifers revealed over-representation of categories, including endosome, cytoplasmic vesicle, endocytosis, regulation of exocytosis, and cytokine receptor activity. Functional categories including transcription factor binding sites, cell motility, and cell migration were enriched for DEGs between endometria from lactating and nonlactating cows. In conclusion, while the evidence for a major effect of lactation on the endometrial transcriptome is relatively weak, these data suggest that the metabolic status of the animal (heifer vs cow) modulates the response of the endometrium to the developing conceptus.

M2 macrophage is the predominant phenotype in airways inflammatory lesions in patients with granulomatosis with polyangiitis

Background

Macrophages may present two distinct phenotypes indicated as M1 and M2 under different stimuli. M1 and M2 macrophages have divergent functions that range from enhancement of inflammation for M1 to tissue repair and remodeling for M2 macrophages. The objective of this study was to evaluate the distribution of M1 and M2 macrophage phenotypes in biopsies from the airways of patients with active granulomatosis with polyangiitis (GPA) and to analyze their associations with T and B cells in those biopsies, and with nasal carriage of Staphylococcus aureus, disease parameters and therapy.

Methods

Consecutive GPA patients (n = 35) with active airway disease, who underwent respiratory tract biopsy were included. Immunohistochemical evaluation was performed to assess the distribution of macrophages and T and B cells using the markers CD68, CD3 and CD20, respectively. CD86 was used as the M1 marker and CD163 as the M2 marker while Tbet and GATA-3 were used as Th1 and Th2 markers, respectively. At the time of the biopsy patients were assessed for nasal carriage of Staphylococcus aureus and treatment.

Results

Percentages of macrophages and T cells were significantly higher than those of B cells in lesional tissue from the respiratory tract in GPA. M2 macrophages and Th2 cells were more frequent than M1 macrophages (p = 0.0007) and Th1 cells (p < 0.0001), respectively. Percentages of T cells were higher in nose biopsies than in biopsies from other sites (p = 0.021); macrophages and CD163⁺ macrophages were more predominant in biopsy sites other than the nose (p = 0.039 and p = 0.012, respectively). Carriage of Staphylococcus aureus was associated with higher T cell scores (p = 0.014). The frequency of macrophages, especially M2 macrophages, was higher in GPA patients treated with immunosuppressive agents (p = 0.010); daily prednisolone dose was positively correlated with all macrophage markers. However, in multivariate analysis no independent associations were found between disease parameters and therapy with macrophage markers or T cells.

Conclusion

In GPA, M2 is the predominant macrophage phenotype in the respiratory tract. Although some associations were observed between macrophages and T cells with therapy and nasal carriage of Staphylococcus aureus, they were not independently significant in multivariate analysis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1310-4) contains supplementary material, which is available to authorized users.

Genetic resistance - an alternative for controlling PRRS?

PRRS is one of the most challenging diseases for world-wide pig production. Attempts for a sustainable control of this scourge by vaccination have not yet fully satisfied. With an increasing knowledge and methodology in disease resistance, a new world-wide endeavour has been started to support the combat of animal diseases, based on the existence of valuable gene variants with regard to any host-pathogen interaction. Several groups have produced a wealth of evidence for natural variability in resistance/susceptibility to PRRS in our commercial breeding lines. However, up to now, exploiting existing variation has failed because of the difficulty to detect the carriers of favourable and unfavourable alleles, especially with regard to such complex polygenic traits like resistance to PRRS. New hope comes from new genomic tools like next generation sequencing which have become extremely fast and low priced. Thus, research is booming world-wide and the jigsaw puzzle is filling up – slowly but steadily. On the other hand, knowledge from virological and biomedical basic research has opened the way for an “intervening way”, i.e. the modification of identified key genes that occupy key positions in PRRS pathogenesis, like CD163. CD163 was identified as the striking receptor in PRRSV entry and its knockout from the genome by gene editing has led to the production of pigs that were completely resistant to PRRSV – a milestone in modern pig breeding. However, at this early step, concerns remain about the acceptance of societies for gene edited products and regulation still awaits upgrading to the new technology. Further questions arise with regard to upcoming patents from an ethical and legal point of view. Eventually, the importance of CD163 for homeostasis, defence and immunity demands for more insight before its complete or partial silencing can be answered. Whatever path will be followed, even a partial abolishment of PRRSV replication will lead to a significant improvement of the disastrous herd situation, with a significant impact on welfare, performance, antimicrobial consumption and consumer protection. Genetics will be part of a future solution.

Respiratory toxicity and immunotoxicity evaluations of microparticle and nanoparticle C60 fullerene aggregates in mice and rats following nose-only inhalation for 13 weeks

C60 fullerene (C60), or buckminsterfullerene, is a spherical arrangement of 60 carbon atoms, having a diameter of approximately 1 nm, and is produced naturally as a by-product of combustion. Due to its small size, C60 has attracted much attention for use in a variety of applications; however, insufficient information is available regarding its toxicological effects. The effects on respiratory toxicity and immunotoxicity of C60 aggregates (50 nm [nano-C60] and 1 μm [micro-C60] diameter) were examined in B6C3F1/N mice and Wistar Han rats after nose-only inhalation for 13 weeks. Exposure concentrations were selected to allow for data evaluations using both mass-based and particle surface area-based exposure metrics. Nano-C60 exposure levels selected were 0.5 and 2 mg/m³ (0.033 and 0.112 m²/m³), while micro-C60 exposures were 2, 15 and 30 mg/m³ (0.011, 0.084 and 0.167 m²/m³). There were no systemic effects on innate, cell-mediated, or humoral immune function. Pulmonary inflammatory responses (histiocytic infiltration, macrophage pigmentation, chronic inflammation) were concentration-dependent and corresponded to increases in monocyte chemoattractant protein (MCP)-1 (rats) and macrophage inflammatory protein (MIP)-1α (mice) in bronchoalveolar lavage (BAL) fluid. Lung overload may have contributed to the pulmonary inflammatory responses observed following nano-C60 exposure at 2 mg/m³ and micro-C60 exposure at 30 mg/m³. Phenotype shifts in cells recovered from the BAL were also observed in all C60-exposed rats, regardless of the level of exposure. Overall, more severe pulmonary effects were observed for nano-C60 than for micro-C60 for mass-based exposure comparisons. However, for surface-area-based exposures, more severe pulmonary effects were observed for micro-C60 than for nano-C60, highlighting the importance of dosimetry when evaluating toxicity between nano- and microparticles.

High mobility group box 1 skews macrophage polarization and negatively influences phagocytosis of apoptotic cells

OBJECTIVES

Decreased phagocytosis of apoptotic cells plays an important role in the pathogenesis of SLE. This can lead to secondary necrosis and release of nuclear proteins, such as high mobility group box 1 (HMGB1). We hypothesized that increased HMGB1 levels, as present in SLE, skew macrophage differentiation towards M1-like phenotypes and thereby diminish uptake of apoptotic cells. The aim of this study was to investigate the effect of HMGB1 on macrophage polarization and on phagocytic capacity of differentiated macrophages.

METHODS

SLE patients with quiescent disease (SLEDAI ⩽4) and healthy controls (HCs) were included. Monocytes and differentiated M1 and M2 macrophages were assessed for expression of M1 and M2 markers and for phagocytic capacity. HMGB1 was added during differentiation and during phagocytosis.

RESULTS

Expression of CD86 (M1) was not different, whereas CD163 (M2) was significantly lower on SLE monocytes. After differentiation, no differences regarding surface receptor expression and phagocytic capacity were observed between M1 and M2 macrophages from SLE patients and HCs. Addition of HMGB1 during M2 differentiation resulted in high IL-6 and TNF-α mRNA expression and reduced phagocytic capacity of apoptotic cells. Furthermore, adding HMGB1 to apoptotic Jurkat cells diminished phagocytosis of these cells.

CONCLUSION

Circulating monocytes from SLE patients display an M1-like phenotype compared with HCs, but in vitro differentiation abolishes this difference. HMGB1 skews differentiation of M2-like macrophages towards an M1-like phenotype and, subsequently, reduces phagocytosis of apoptotic cells. These data imply that the phenotype of monocytes or macrophages is determined by their environment, such as the presence of cytokines and HMGB1.

The New Role of CD163 in the Differentiation of Bone Marrow Stromal Cells into Vascular Endothelial-Like Cells

Bone marrow stromal cells (BMSCs) can differentiate into vascular endothelial cells (VECs). It is regarded as an important solution to cure many diseases, such as ischemic diseases and diabetes. However, the mechanisms underlying BMSC differentiation into VECs are not well understood. Recent reports showed that CD163 expression was associated with angiogenesis. In this study, overexpression of CD163 in BMSCs elevated the protein level of the endothelial-associated markers CD31, Flk-1, eNOS, and VE-cadherin, significantly increased the proportion of Alexa Fluor 488-acetylated-LDL-positive VECs, and promoted angiogenesis on Matrigel. Furthermore, we demonstrated that CD163 acted downstream homeobox containing 1 (Hmbox1) and upstream fibroblast growth factor 2 (FGF-2). These data suggested that CD163 was involved in Hmbox1/CD163/FGF-2 signal pathway in BMSC differentiation into vascular endothelial-like cells. We found a new signal pathway and a novel target for further investigating the gene control of BMSC differentiation into a VEC lineage.

Macrophage Activation Syndrome-Associated Markers in Severe Dengue

Hemophagocytosis, a phenomenon of which activated macrophages phagocytosed hematopoietic elements was reportedly observed in severe dengue patients. In the present study, we investigated whether markers of macrophage activation syndrome (MAS) can be used as differential diagnostic markers of severe dengue. Two hundred and eight confirmed dengue patients were recruited for the study. Sandwich ELISA was used to determine serum ferritin, soluble CD163 (sCD163), and soluble CD25 (sCD25) levels. The population of circulating CD163 (mCD163) monocytes was determined using flow cytometry. Receiver operating characteristic (ROC) analysis was plotted to determine the predictive validity of the biomarkers. Serum ferritin and sCD163 were found significantly increased in severe dengue patients compared to dengue fever patients (P = 0.003). A fair area under ROC curves (AUC) at 0.72 with a significant P value of 0.004 was observed for sCD163. sCD25 and mCD163 levels were not significantly different between severe dengue and dengue fever patients. Our findings suggest that in addition to serum ferritin, sCD163 can differentiate severe dengue from that of dengue fever patients. Hence, sCD163 level can be considered for use as a predictive marker for impending severe dengue.

Brief Glutamine Pretreatment Increases Alveolar Macrophage CD163/Heme Oxygenase-1/p38-MAPK Dephosphorylation Pathway and Decreases Capillary Damage but Not Neutrophil Recruitment in IL-1/LPS-Insufflated Rats

Background

Glutamine (GLN) attenuates acute lung injury (ALI) but its effect on alveolar macrophages is unknown. We hypothesized that GLN pretreatment would induce the anti-inflammatory CD163/heme oxygenase (HO)-1/p38-MAPK dephosphorylation pathway in alveolar macrophages and reduce ALI in rats insufflated with interleukin-1 (IL-1) and lipopolysaccharide (LPS).

Methods

Male Sprague-Dawley rats were randomized to the following groups: GLN-IL-1/LPS-, GLN+IL-1/LPS-, GLN-IL-1/LPS+, and GLN+IL-1/LPS+. GLN pretreatment was given via gavage (1g/kg L-alanyl-L-glutamine) daily for 2 days. ALI was subsequently induced by insufflating 50ng IL-1 followed by 5mg/kg E.coli LPS. After 24h, bronchoalveolar lavage (BAL) protein, lactate dehydrogenase (LDH) and neutrophil concentrations were analyzed. BAL alveolar macrophage CD163+ expression, HO-1 and p38-MAPK concentrations were measured, as well as alveolar macrophage tumor necrosis factor (TNF)-α and interleukin (IL)-10 concentrations. Histology and immunofluorescence studies were also performed.

Results

Following IL-1/LPS insufflation, GLN pretreated rats had significantly decreased BAL protein and LDH concentrations, but not BAL neutrophil counts, compared to non-GLN pretreated rats. The number of alveolar macrophages and the number of CD163+ macrophages were significantly increased in GLN pretreated IL-1/LPS-insufflated rats compared to non-GLN pretreated, IL-1/LPS-insufflated rats. GLN pretreatment before IL-1/LPS also significantly increased HO-1 concentrations and dephosphorylated p38-MAPK levels but not cytokine levels in alveolar macrophages. Immunofluorescence localized CD163 and HO-1 in alveolar macrophages.

Conclusion

Short-term GLN pretreatment activates the anti-inflammatory CD163/HO-1/p38-MAPK dephosphorylation pathway of alveolar macrophages and decreases capillary damage but not neutrophil recruitment in IL-1/LPS-insufflated rats.

AIM/CD5L: a key protein in the control of immune homeostasis and inflammatory disease

CD5L, a soluble protein belonging to the SRCR superfamily, is expressed mostly by macrophages in lymphoid and inflamed tissues. The expression of this protein is transcriptionally controlled by LXRs, members of the nuclear receptor family that play major roles in lipid homeostasis. Research undertaken over the last decade has uncovered critical roles of CD5L as a PRR of bacterial and fungal components and in the control of key mechanisms in inflammatory responses, with involvement in processes, such as infection, atherosclerosis, and cancer. In this review, we summarize the current knowledge of CD5L, its roles at the intersection between lipid homeostasis and immune response, and its potential use as a diagnostic biomarker in a variety of diseases, such as TB and liver cirrhosis.

PRRS virus receptors and their role for pathogenesis

Porcine reproductive and respiratory syndrome virus (PRRSV) is endemic in most pig producing countries worldwide and causes enormous economic losses to the swine industry. Specifically differentiated porcine alveolar macrophages are the primary target for PRRSV infection in pigs. At least six cellular molecules have been described so far as putative receptors for PRRSV, and they include heparan sulfate, vimentin, CD151, sialoadhesin (CD169; siglec-1), dendritic cell-specific intercellular adhesion melecule-3-grabbing non-integrin (DC-SIGN; CD209), and CD163 (SRCR, cysteine-rich scavenger receptor). Progress has been made to shed light on the interactions between cells and PRRSV, and this review describes the advances and current understanding of the entry of PRRSV to cells with a particular focus on the role of CD163 and sialoadhesin for infection and PRRSV pathogenesis. CD163 is most likely the primary and core receptor for PRRSV and determines the susceptibility of cells to the virus. Sialoadhesin is either unnecessary for infection or may function as an accessory protein. Sialoadhesin has been mostly studied for genotype I PRRSV whereas the utilization of CD163 has been mostly studied using genotype II PRRSV, and whether each genotype indeed utilizes a different receptor is unclear.

Soluble Scavenger Receptor CD163 Is Associated with Severe Acute Kidney Injury in Patients with Hantaan Virus Infection

CD163, a hemoglobin scavenger receptor for haptoglobin-hemoglobin complexes, is expressed by monocytes/macrophages and is often shed as soluble CD163 (sCD163) in response to inflammatory stimuli. This scavenger receptor is reported to dampen the inflammatory response, and high plasma levels of sCD163, which are thought to reflect the total level of CD163 expression, may predict the severity of disease. To understand the role of sCD163 in the pathogenesis of hemorrhagic fever with renal syndrome (HFRS) better, the concentrations of sCD163 in plasma from 66 patients were quantified, and the relationships between sCD163 level and disease course, severity, and clinical parameters were analyzed. The level of plasma sCD163 in HFRS patients was elevated from fever onset and during the course of the disease, and it peaked in the oliguria stage at 874.5 (549.9-1138.0) ng/mL compared with controls at 192.8 (54.9-282.1) ng/mL. The correlations between plasma sCD163 and renal dysfunction suggest that sCD163 may play an important role in the development of acute renal failure in patients infected with Hantaan virus.

Chronic rhinosinusitis and cystic fibrosis: the interaction between sinus bacteria and mucosal immunity

BACKGROUND

Chronic rhinosinusitis (CRS) is highly prevalent in cystic fibrosis (CF) patients, in whom a close correlation exists between the microbiology of the upper and lower respiratory tracts. We have reported intramucosal bacterial microcolonies in the sinus mucosa from idiopathic CRS patients and have made observations suggesting that these may result from mucosal immunotolerance secondary to altered macrophage function. In this study, we sought to determine whether intramucosal microcolonies exist in the mucosa of CF patients with CRS, and to investigate the associated mucosal immunology.

METHODS

Mucus swabs and tissue biopsies were taken from 9 patients with CF undergoing functional endoscopic sinus surgery (FESS) for CRS, 11 with idiopathic CRS undergoing FESS, and 9 with normal sinuses having transnasal pituitary surgery. Microbiology samples were taken for culture and intramucosal microcolonies were sought using Gram staining. Mucosal immune cells were identified using fluorescent immunohistochemistry.

RESULTS

Positive culture rates were similar between CRS patients and controls, but there were significantly more intramucosal microcolonies in the CRS groups (8/9 CF-CRS, 7/11 CRS), compared to controls (1/9). Furthermore, the biodensity of intramucosal microcolonies was significantly higher in CF-CRS than idiopathic CRS. Mirroring the microbiological observations, the number of CD163+ macrophages was significantly increased in CF-CRS compared to idiopathic CRS (p = 0.03).

CONCLUSION

Intramucosal bacteria exist within the sinus mucosa of patients with CF, and in significantly greater numbers than in idiopathic CRS patients. We speculate that intramucosal microcolonies may also exist in the lower respiratory tract mucosa in CF and play a role in disease recalcitrance.

M2 macrophage infiltrates in the early stages of ANCA-associated pauci-immune necrotizing GN

BACKGROUND AND OBJECTIVES

This study examined kidney biopsies with focal segmental glomerular fibrinoid necrosis to identify early features of pauci-immune necrotizing GN and the primary effector cells mediating initial capillary injury.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Seventeen consecutive kidney biopsies with focal pauci-immune necrotizing GN, obtained over a 6-year period (2007-2012), were studied. Neutrophils and CD68(+), CD163(+), CD3(+), CD56(+), and CD20(+) cells were scored in paraffin sections counterstained with periodic acid-Schiff. Electron microscopy was performed in 15 of 17 biopsies and additional examples of pauci-immune necrotizing GN (n=25). Biopsies with thin basement membrane nephropathy (n=5) served as immunohistologic normal controls.

RESULTS

Biopsies with pauci-immune necrotizing GN had a mean of 10 (range=3-25) normal-appearing glomeruli, a mean of 2 (range=1-5) glomeruli with segmental fibrinoid necrosis, and a mean of 2 (range=1-11) glomeruli with cellular crescents. CD68(+) and CD163(+) macrophages predominated at sites of fibrinoid necrosis in pauci-immune necrotizing GN, exceeding the quantity of neutrophils and T cells (mean scores [SD]=2.5 [0.7] and 2.2 [0.75] versus 0.6 [0.5] and 0.1 [0.3], respectively; P<0.001). B and natural killer cells were rare. Normal-appearing glomeruli in pauci-immune necrotizing GN had significantly more CD68(+) and CD163(+) macrophages than the controls (CD68(+), 0.9 [0.3] versus 0.4 [0.3]; CD163(+), 1 [0.4] versus 0.4 [0.3]; P<0.001). The quantity of other glomerular infiltrates did not differ from controls. The serum creatinine level at biopsy correlated with the glomerular CD68 and neutrophil scores (r=0.74 and r=0.71, respectively; P=0.001) but did not correlate with the extent of fibrinoid necrosis (r=0.36). Macrophages were localized at minute perforations and attenuations of the capillary basement membrane by electron microscopy.

CONCLUSIONS

Early pauci-immune necrotizing GN is characterized by a selective localization of CD163(+) M2 macrophages at sites of glomerular fibrinoid necrosis and in normal-appearing glomeruli. These observations indicate that alternatively activated macrophages are positioned as potential effectors of glomerular injury in the early stages of pauci-immune necrotizing GN and may be potential targets for therapeutic intervention.

Macrophages and dendritic cells as actors in the immune reaction of classical Hodgkin lymphoma

BACKGROUND

The inflammatory infiltrate plays a pivotal role in classical Hodgkin lymphoma (cHL). Here, we focussed on the role of macrophages (MΦ) and dendritic cells (DC).

METHODS

MΦ and DC infiltration was investigated in 106 cHL specimens using immunohistochemistry and cytokine expression was analyzed in a subset by real-time PCR. Human peripheral blood-derived monocytes, DC, MΦ stimulated with GM-CSF (MΦGM-CSF, pro-inflammatory MΦ-1-model) or M-CSF (MΦM-CSF, immunomodulatory MΦ-2-model) were incubated with cHL cell line (L1236, HDLM2) supernatants (SN). DC maturation or MΦ polarization were investigated by flow cytometry. Furthermore, the impact of DC or MΦ on cHL cell proliferation was analyzed by BrdU/CFSE assay.

RESULTS

In cHL tissues mature myeloid (m)DC and MΦ predominated. High numbers of CD83+ mDC and low numbers of CD163+ MΦ were associated with improved disease specific survival. In numerous cHL specimens increased levels of both pro- and anti-inflammatory cytokines and of IL13 and GM-CSF were observed compared to reactive lymphadenopathies. Maturation of DC and induction and maintenance of an immunomodulatory MΦ phenotype were promoted by SN derived from cHL cell lines. TNFα neutralization in SN resulted in a significant inhibition of mDC maturation. DC and pro-inflammatory MΦ inhibited the proliferation of cHL cells.

CONCLUSION

Adopting an immunomodulatory phenotype is a potential mechanism for how MΦ promote immune evasion in cHL. Mature DC, in contrast, might participate in antitumoral immunity.

Lenalidomide interferes with tumor-promoting properties of nurse-like cells in chronic lymphocytic leukemia

Lenalidomide is an immunomodulatory agent clinically active in chronic lymphocytic leukemia patients. The specific mechanism of action is still undefined, but includes modulation of the microenvironment. In chronic lymphocytic leukemia patients, nurse-like cells differentiate from CD14(+) mononuclear cells and protect chronic lymphocytic leukemia cells from apoptosis. Nurse-like cells resemble M2 macrophages with potent immunosuppressive functions. Here, we examined the effect of lenalidomide on the monocyte/macrophage population in chronic lymphocytic leukemia patients. We found that lenalidomide induces high actin polymerization on CD14(+) monocytes through activation of small GTPases, RhoA, Rac1 and Rap1 that correlated with increased adhesion and impaired monocyte migration in response to CCL2, CCL3 and CXCL12. We observed that lenalidomide increases the number of nurse-like cells that lost the ability to nurture chronic lymphocytic leukemia cells, acquired properties of phagocytosis and promoted T-cell proliferation. Gene expression signature, induced by lenalidomide in nurse-like cells, indicated a reduction of pivotal pro-survival signals for chronic lymphocytic leukemia, such as CCL2, IGF1, CXCL12, HGF1, and supported a modulation towards M1 phenotype with high IL2 and low IL10, IL8 and CD163. Our data provide new insights into the mechanism of action of lenalidomide that mediates a pro-inflammatory switch of nurse-like cells affecting the protective microenvironment generated by chronic lymphocytic leukemia into tissues.

The interaction between bacteria and mucosal immunity in chronic rhinosinusitis: a prospective cross-sectional analysis

BACKGROUND

We have detected intramucosal bacteria within the sinus mucosa of patients with chronic rhinosinusitis (CRS), but our attempts at characterizing these did not yield any discernible genotypic or phenotypic differences from surface bacteria. We hypothesized that the presence of intramucosal microcolonies reflected host mucosal immune dysfunction. This study characterizes the activation status of T cells, B cells, and macrophages in the sinus mucosa of patients with CRS and controls and determines the impact of bacteria on mucosal immunology.

METHODS

Swabs and mucosal biopsy specimens were taken from 27 patients with CRS undergoing sinus surgery and 9 patients with normal sinuses having transnasal pituitary surgery. Microcolonies were detected using Gram staining, and the immune cells were characterized by immunohistochemical techniques.

RESULTS

Swab culture rates for Staphylococcus aureus were similar between CRS and controls. However, there were significantly more intramucosal microcolonies in CRS (59% versus 11%) than in controls (p = 0.02). There were significantly more immune cells in CRS. Percentage of activated T and B cells were similar between CRS and controls, but there were significantly more CD163(+) M2 macrophages in patients with CRS (p = 0.0004). Furthermore, percentage of CD163(+) macrophages showed a positive correlation with disease severity. The presence of bacteria had no impact on immunology or disease severity.

CONCLUSION

Tolerance of intramucosal microcolonies in CRS may reflect altered macrophage function in the host mucosa. The clinical severity of CRS is also dependent on the host mucosa immune dysfunction, rather than the presence of intramucosal microcolonies.

In women with previous pregnancy hypertension, levels of cardiovascular risk biomarkers may be modulated by haptoglobin polymorphism

Preeclampsia (PE) may affect the risk for future cardiovascular disease. Haptoglobin (Hp), an acute phase protein with functional genetic polymorphism, synthesized in the hepatocyte and in many peripheral tissues secondary of oxidative stress of PE, may modulate that risk through the antioxidant, angiogenic, and anti-inflammatory differential effects of their genotypes. We performed a prospective study in 352 women aged 35 ± 5.48 years, which 165 had previous PE, 2 to 16 years ago. We studied demographic, anthropometric, and haemodynamic biomarkers such as C-reactive protein (CRP), myeloperoxidase (MPO), and nitric oxide metabolites (total and nitrites), and others associated with liver function (AST and ALT) and lipid profile (total LDL and cholesterol HDL, non-HDL, and apolipoproteins A and B). Finally, we study the influence of Hp genetic polymorphism on all these biomarkers and as a predisposing factor for PE and its remote cardiovascular disease prognosis. Previously preeclamptic women either hypertensive or normotensive presented significant differences in those risk biomarkers (MPO, nitrites, and ALT), whose variation may be modulated by Hp 1/2 functional genetic polymorphism. The history of PE may be relevant, in association with these biomarkers to the cardiovascular risk in premenopausal women.

Neuroinflammation and M2 microglia: the good, the bad, and the inflamed

The concept of multiple macrophage activation states is not new. However, extending this idea to resident tissue macrophages, like microglia, has gained increased interest in recent years. Unfortunately, the research on peripheral macrophage polarization does not necessarily translate accurately to their central nervous system (CNS) counterparts. Even though pro- and anti-inflammatory cytokines can polarize microglia to distinct activation states, the specific functions of these states is still an area of intense debate. This review examines the multiple possible activation states microglia can be polarized to. This is followed by a detailed description of microglial polarization and the functional relevance of this process in both acute and chronic CNS disease models described in the literature. Particular attention is given to utilizing M2 microglial polarization as a potential therapeutic option in treating diseases.

Human macrophage polarization in vitro: maturation and activation methods compared

Macrophages form a heterogeneous cell population displaying multiple functions, and can be polarized into pro- (M1) or anti-inflammatory (M2) macrophages, by environmental factors. Their activation status reflects a beneficial or detrimental role in various diseases. Currently several in vitro maturation and activation protocols are used to induce an M1 or M2 phenotype. Here, the impact of different maturation factors (NHS, M-CSF, or GM-CSF) and activation methods (IFN-γ/LPS, IL-4, dexamethason, IL-10) on the macrophage phenotype was determined. Regarding macrophage morphology, pro-inflammatory (M1) activation stimulated cell elongation, and anti-inflammatory (M2) activation induced a circular appearance. Activation with pro-inflammatory mediators led to increased CD40 and CD64 expression, whereas activation with anti-inflammatory factors resulted in increased levels of MR and CD163. Production of pro-inflammatory cytokines was induced by activation with IFN-γ/LPS, and TGF-β production was enhanced by the maturation factors M-CSF and GM-CSF. Our data demonstrate that macrophage marker expression and cytokine production in vitro is highly dependent on both maturation and activation methods. In vivo macrophage activation is far more complex, since a plethora of stimuli are present. Hence, defining the macrophage activation status ex vivo on a limited number of markers could be indecisive. From this study we conclude that maturation with M-CSF or GM-CSF induces a moderate anti- or pro-inflammatory state respectively, compared to maturation with NHS. CD40 and CD64 are the most distinctive makers for human M1 and CD163 and MR for M2 macrophage activation and therefore can be helpful in determining the activation status of human macrophages ex vivo.

Liver myofibroblasts up-regulate monocyte CD163 expression via PGE2 during hepatitis B induced liver failure

Background

Although patients with liver failure exhibit a generalized inflammatory-imbalance status, substantial evidence indicates that this immunosuppressive or anti-inflammatory state may be deleterious. Increased expression of CD163 (known to be involved in several anti-inflammatory functions of the immune system) in patients with liver failure is significantly correlated with a fatal outcome. However, little is known of the regulatory mechanisms that influence the expression of CD163.

Methods

We assessed the expression of CD163 on monocytes from both circulating cells and the liver tissues of patients with hepatitis B induced liver failure using flow cytometry and isolated the myofibroblasts from diseased livers. The ability of human liver myofibroblasts to regulate CD163 expression on monocytes was studied in vitro.

Results

We showed that CD163⁺ monocytes were enriched primarily in diseased livers and that they were associated with liver myofibroblasts in the same area. Accordingly, liver myofibroblasts were significantly superior to normal skin fibroblasts in inducing the expression of CD163 on monocytes in vitro. Moreover, we found that liver myofibroblasts triggered the activation of monocytes by secreting PGE2. Inhibition of PGE2 production in liver myofibroblasts using NS-398 markedly reduced CD163 expression in vitro.

Conclusion

These results suggest that liver myofibroblasts play a direct role in regulating the expression of CD163 on monocytes in human liver tissues and thereby may regulate monocyte function during hepatitis B induced liver failure.

Overexpression of CD163, CD204 and CD206 on alveolar macrophages in the lungs of patients with severe chronic obstructive pulmonary disease

We have previously reported that the lungs of patients with very severe chronic obstructive pulmonary disease (COPD) contain significantly higher numbers of alveolar macrophages than those of non-smokers or smokers. M1 and M2 macrophages represent pro- and anti-inflammatory populations, respectively. However, the roles of M1 and M2 alveolar macrophages in COPD remain unclear. Immunohistochemical techniques were used to examine CD163, CD204 and CD206, as M2 markers, expressed on alveolar macrophages in the lungs of patients with mild to very severe COPD (Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage I (mild) n = 11, II (moderate) n = 9, III (severe) n = 2, and IV (very severe) n = 16). Fifteen smokers and 10 non-smokers were also examined for comparison. There were significantly higher numbers of alveolar macrophages in COPD patients than in smokers and non-smokers. The numbers and percentages of CD163(+), CD204(+) or CD206(+) alveolar macrophages in patients with COPD at GOLD stages III and IV were significantly higher than in those at GOLD stages I and II, and those in smokers and non-smokers. In patients with COPD, there was a significant negative correlation between the number of CD163(+), CD204(+) or CD206(+) alveolar macrophages and the predicted forced expiratory volume in one second. Overexpression of CD163, CD204 and CD206 on lung alveolar macrophages may be involved in the pathogenesis of COPD.

Impacts of the apoptosis inhibitor of macrophage (AIM) on obesity-associated inflammatory diseases

Obesity is associated with various metabolic and cardiovascular diseases caused by chronic, low-grade inflammation that is initially observed in obese adipose tissue. In addition, many etiological studies in humans have shown a strong correlation between obesity and inflammatory autoimmune diseases. In this review, we focus on the involvement of apoptosis inhibitor of macrophage (AIM), a macrophage-derived blood protein, in both types of immune response. Through differential mechanisms, AIM thereby plays key roles in the pathogenesis of atherosclerosis, metabolic diseases, and obesity-associated autoimmune diseases. Thus, the regulation of blood AIM levels or AIM function has the potential to serve as a next-generation therapy against these inflammatory diseases brought about by modern lifestyle.

The Gottingen minipig is a model of the hematopoietic acute radiation syndrome: G-colony stimulating factor stimulates hematopoiesis and enhances survival from lethal total-body γ-irradiation

PURPOSE

We are characterizing the Gottingen minipig as an additional large animal model for advanced drug testing for the acute radiation syndrome (ARS) to enhance the discovery and development of novel radiation countermeasures. Among the advantages provided by this model, the similarities to human hematologic parameters and dynamics of cell loss/recovery after irradiation provide a convenient means to compare the efficacy of drugs known to affect bone marrow cellularity and hematopoiesis.

METHODS AND MATERIALS

Male Gottingen minipigs, 4 to 5 months old and weighing 9 to 11 kg, were used for this study. We tested the standard off-label treatment for ARS, rhG-CSF (Neupogen, 10 μg/kg/day for 17 days), at the estimated LD70/30 total-body γ-irradiation (TBI) radiation dose for the hematopoietic syndrome, starting 24 hours after irradiation.

RESULTS

The results indicated that granulocyte colony stimulating factor (G-CSF) enhanced survival, stimulated recovery from neutropenia, and induced mobilization of hematopoietic progenitor cells. In addition, the administration of G-CSF resulted in maturation of monocytes/macrophages.

CONCLUSIONS

These results support continuing efforts toward validation of the minipig as a large animal model for advanced testing of radiation countermeasures and characterization of the pathophysiology of ARS, and they suggest that the efficacy of G-CSF in improving survival after total body irradiation may involve mechanisms other than increasing the numbers of circulating granulocytes.

Articular adipose tissue resident macrophages in rheumatoid arthritis patients: potential contribution to local abnormalities

OBJECTIVES

The objectives of this study were to characterize macrophages resident in inflamed articular adipose tissue (AAT) and non-inflamed subcutaneous adipose tissue (ScAT) of RA patients and to evaluate the basal and cytokine-triggered secretory activities of these tissues.

METHODS

Tissues were obtained from patients undergoing knee joint replacement surgery. The number of total CD68(+), CD14(+) and CD163(+) macrophages was evaluated by immunohistochemistry. The concentrations of select factors were measured in supernatants from untreated and cytokine-treated tissue explant cultures using ELISA. IL-1β and TNF were applied as the stimuli.

RESULTS

Paired samples of AAT and ScAT, obtained from the same patients, contained a similar number of macrophages, displaying an M2-skewed phenotype. Both tissues released equivalent amounts of IL-1β, TNF, IL-10 and macrophage migration inhibitory factor (MIF). However, AAT secreted more chemokines (CCL2, CCL5), cytokines [IL-6, IL-8, IL-1 receptor antagonist (IL-1Ra)], hepatocyte growth factor (HGF) and MMP-3 than ScAT. Basal secretion of adipocytokines was not patient specific. Except for HGF and MIF, cytokine treatment up-regulated the release of these factors from both tissues, but also upon stimulation AAT produced more IL-6, IL-8 and IL-1Ra than ScAT.

CONCLUSION

The secretory activity, reflecting cell activation status but not phenotype or the number of macrophages, discriminates rheumatoid AAT from ScAT. By releasing various factors possessing chemotactic, proinflammatory, anti-inflammatory and tissue degrading activities, AAT resident macrophages may drive and control local pathological processes.

Comparative assessment of cytokines and other inflammatory markers for the early diagnosis of neonatal sepsis-a case control study

OBJECTIVE

Cytokines (IL-6, IL-8 and TNF-α), sCD163, and C-reactive protein were serially measured in an attempt to identify a set of tests which can reliably confirm or refute the diagnosis of neonatal sepsis at an early stage.

METHODS

One hundred neonates suspected to have sepsis on clinical grounds and who met the inclusion criteria were enrolled for the study. Based on the positive or negative blood culture reports they were classified as infected (n=50) and non-infected (n=50) neonates respectively. Fifty healthy neonates without any signs of sepsis were also included in the study as control group. The initial blood sample was taken on day 0 (at the time of sepsis evaluation) and two further samples were taken on days 1 and 2 for monitoring the clinical progress and response to treatment. In the control group the cord blood and 48 hours venous sample was collected. Plasma CRP (ng/ml), IL-6 (pg/ml), IL-8 (pg/ml), TNF-α (ng/ml) and sCD163 (ng/ml) were determined by double antibody method Enzyme Linked Immunosorbent Assay in all the three blood samples.

RESULTS

The cut of levels for CRP at >19,689 ng/ml had a sensitivity of 68%, specificity of 92%, for IL-6 at >95.32 pg/ml had a sensitivity of 54%, specificity of 96%, for IL-8 at >70.86 pg/ml had a sensitivity of 78%, specificity of 70%, for sCD163 at >896.78 ng/ml had a sensitivity of 100%, specificity of 88% for the diagnosis of infection before antibiotics. TNF-α levels of >12.6 ng/ml showed 100% sensitivity and 72% specificity for the diagnosis of inflammation.

CONCLUSION

The most powerful predictor to differentiate between the non-infected and infected neonates before antibiotics was sCD163. The most powerful indicator for evaluation of prognosis is IL-6. sCD163 can be used alone to screen for sepsis in neonates before the results of blood culture are received.

The Placenta in Toxicology. Part II

During pregnancy, the maternal immune system is challenged by the semiallogeneic fetus, which must be tolerated without compromising fetal or maternal health. This review updates the systemic and local immune changes taking place during human pregnancy, including some examples in rodents. Systemic changes are induced by contact of maternal blood with placental factors and include enhanced innate immunity with increased activation of granulocytes and nonclassical monocytes. Although a bias toward T helper (Th2) and regulatory T cell (Treg) immunity has been associated with healthy pregnancy, the relationship between different circulating Th cell subsets is not straightforward. Instead, these adaptations appear most evidently at the fetal–maternal interface, where for instance Tregs are enriched and promote fetal tolerance. Also innate immune cells, that is, natural killer cells and macrophages, are enriched, constituting the majority of decidual leukocytes. These cells not only contribute to immune regulation but also aid in establishing the placenta by promoting trophoblast recruitment and angiogenesis. Thus, proper interaction between leukocytes and placental trophoblasts is necessary for normal placentation and immune adaptation. Consequently, spontaneous maladaptation or interference of the immune system with toxic substances may be important contributing factors for the development of pregnancy complications such as preeclampsia, preterm labor, and recurrent miscarriages.

Intestinal epithelial CD98 synthesis specifically modulates expression of colonic microRNAs during colitis

The transmembrane glycoprotein CD98 is known to be involved in intestinal inflammation. In the present study, we found that CD98 overexpression in intestinal epithelial cells does not normally affect the expression of colonic (epithelial and immune cell) microRNAs (miRNAs), small noncoding RNAs that posttranscriptionally regulate a wide variety of biological processes. However, upon dextran sulfate sodium (DSS) treatment, the expression of several colonic miRNAs, but not miRNAs from other tissues such as liver and spleen, were differentially regulated in mice overexpressing CD98 in epithelial cells compared with wild-type (WT) animals. For example, the level of colonic miRNA 132 was not affected by DSS treatment in WT animals but was upregulated in mice overexpressing CD98 in intestinal epithelial cells. Other colonic miRNAs, including colonic miRNA 23a and 23b, were downregulated in WT animals after DSS treatment but not in colonic epithelial cell CD98-overexpressing mice. Interestingly, the expression of potential miRNA target genes affected intestinal epithelial cells that overexpress CD98 and cell types that did not overexpress CD98 but were in close proximity to CD98-overexpressing intestinal epithelial cells. Taken together, these observations show that the combination of an inflammatory context and intestinal epithelial cell expression of CD98 affects the regulation of miRNA expression in colonic epithelial and immune cells. This is new evidence that protein expression modulates miRNA expression and suggests the existence of regulatory crosstalk between proteins and miRNAs in diseases such as colitis.