Polymorphonuclear Neutrophil Infiltration Research Articles

The effect of Betanin parenteral pretreatment on Jejunal and pulmonary tissue histological architecture and inflammatory response after Jejunal ischemia-reperfusion injury

Intestinal ischemic-reperfusion (IR) injury has detrimental effects on both local and distant organs in the body. Betanin is known for its antioxidant properties, and it is found mostly in vegetables. Therefore, the aim of the present study was to test the hypothesis that betanin administration prior intestinal IR, may be beneficial in protecting jejunal mucosa and lung parenchyma against IR damage. Male specific pathogen-free Charles River Wistar rats were used (n = 42). Betanin (50 mg/kg) was administered intraperitoneally 30 min before ischemia of the superior mesenteric artery lasting 1 h, followed by 1, 4 and 24 h of reperfusion. Immunohistochemical as well as histomorphometrical analysis indicated a protective effect of betanin pretreatment on jejunal tissue. Regarding morphometrical analysis betanin significantly (p < 0.01) augments intestinal villus height after 24 of reperfusion comparing to early stages. Betanin application reduced number of mast cells population in early reperfusion periods (p < 0.05). The protective effect of betanin on lung parenchyma, was detected in late reperfusion period (24 h) with improvement of histopathological injury index and morphometric analysis (p < 0.001 for both). The improvement of histopathological injury index (p < 0.001) and morphometric analysis (p < 0.001) during the late reperfusion period, suggests a protective effect of betanin on lung parenchyma. Moreover, suppression of the inflammatory response was mirrored by the reduction of myeloperoxidase (MPO) positive cells within lung parenchyma after 1 and 4 h of reperfusion (p < 0.001). Especially, during the first 4 h of reperfusion after betanin administration, a reduction of 74% of the polymorphonuclear neutrophils infiltration (MPO positive cell population) and of a nearly 46% of active MCs was observed. Upon morphometric examination, the lung histological architecture after 24 h of reperfusion appeared to be almost 100% better following betanin treatment, with 25% thinner interalveolar septa and 20% larger alveolar surface for respiratory gas exchange. The results suggest that betanin pretreatment protects the jejunal mucosa and the lung parenchyma, as well as reduces the inflammatory cell density after intestinal IR injury.

Minthostachys verticillata essential oil activates macrophage phagocytosis and modulates the innate immune response in a murine model of Enterococcus faecium mastitis

Minthostachys verticillata essential oil (EO) is a natural product that reports immunomodulatory effects on human T cells as well as anti-inflammatory activity. Bovine mastitis is a worldwide disease, mainly caused by bacteria, affecting milk quality and yield, leading to high economic losses. Environmental pathogens, as Enterococcus faecium, are implicated in the disease. Antibiotic therapy is adequate, although it can leave residues in milk, causing problems in human health. The search of immunomodulatory substances for bovine mastitis treatment is a promising alternative strategy. The aim of this study was to characterize the effect of M. verticillata EO on macrophage phagocytosis and evaluate its immunomodulatory and protective effects in mice challenged with E. faecium. The results showed that EO activated macrophage phagocytosis mechanisms inducing reactive oxygen species production. Moreover, EO modulated the innate immune response in mammary glands of female Balb/c mice challenged with E. faecium decreasing the infiltration of polymorphonuclear neutrophils and IL-1β and TNF-α mRNA expression. In addition, EO increased the expression of IL-10 in the last hours of infection. Treatment with EO did not increase the number of activated CD4+ or CD8+ T cells or the production of specific antibodies. These results suggest that EO play an important role in helping to resolve the infection in the first hours without activating adaptive immunity. In addition, a marked decrease of the bacterial count in the glands of mice treated with EO was observed. A natural product such as M. verticillata EO could have a potential use to control bovine mastitis.

Internalization, distribution, and activity of peptide H2 against the intracellular multidrug-resistant bovine mastitis-causing bacterium Staphylococcus aureus

Bovine mastitis is mainly caused by Staphylococcus aureus, which is difficult to eliminate, prone to escape from antibacterial agents, and may cause recurring infections due to the intracellular nature of its infection and multidrug resistance. In this study, the intracellular activities of the NZ2114 derivative peptide H18R (H2) against methicillin-resistant S. aureus (MRSA) and multidrug-resistant bovine S. aureus strains were investigated in bovine mammary epithelial MAC-T cells and mouse mammary glands. The minimum inhibitory concentrations of H2 against S. aureus were 0.5‒1 μg/ml; H2 displayed a lower cytotoxicity than its parental peptide NZ2114 (survival rates of MAC-T cells: 100% [H2 treatment] vs 60.7% [NZ2114 (256 μg/ml) treatment]). H2 was internalized into MAC-T cells mainly via clathrin-mediated endocytosis, and distributed in the cytoplasm. The intracellular inhibition rates against MRSA ATCC43300, the mastitis isolates S. aureus CVCC 3051 and E48 were above 99%, 99%, and 94%, respectively; these were higher than those in case of vancomycin (23–47%). In the mouse model of S. aureus E48-induced mastitis, after treatment with 100 μg of H2 and vancomycin, bacterial numbers in each mammary gland were reduced by 3.96- and 1.59-log CFU, respectively. Additionally, similar to NZ2114 and vancomycin, H2 alleviated the histopathological damage of the mammary tissue and polymorphonuclear neutrophil infiltration in the alveoli. These results suggest that H2 can be used as a safe and effective candidate for treating S. aureus-induced mastitis.

RETRACTED: Up-regulation of ANXA1 suppresses polymorphonuclear neutrophil infiltration and myeloperoxidase activity by activating STAT3 signaling pathway in rat models of myocardial ischemia-reperfusion injury

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief and authors. The authors reported that the paper had been submitted without permission of all authors (specifically Professor Wu). When asked to respond to alleged image manipulation by ‘Hoya camphorifolia’ in Fig. 8B and western blots, they responded that they regret the mistakes in figure 8B and that their technical collaborators could not provide the original images of the Western blots in this paper. The authors apologise for any misconceptions that this paper may have resulted in.

Impaired Peritoneal Macrophage Function and Delayed Neutrophil Recruitment are Secondary to a Leaky Gut in JAM‐A Deficient Mice

Junctional adhesion molecule‐A (JAM‐A) is a transmembrane glycoprotein expressed on leukocytes, endothelia and epithelia that regulates endothelial/epithelial barrier function as well as leukocyte transendothelial/transepithelial migration. While biological roles of JAM‐A have been extensively studied with JAM‐A knockout mice (Jam‐a KO), tissue‐specific JAM‐A deficient animals remain poorly documented. Therefore, we generated mice with tissue selective deletion of JAM‐A in myelomonocytic cells (LysM‐cre; Jam‐a fl/fl) and the intestinal epithelium (Villin‐cre; Jam‐a fl/fl). We then used an acute peritonitis model induced by intraperitoneal injection of zymosan or lipopolysaccharide (LPS) to study the role of tissue selective expression of JAM‐A in recruitment of polymorphonuclear neutrophils (PMN). Consistent with previous reports, infiltration of PMN into the peritoneum in response to zymosan or LPS was significantly reduced in Jam‐a KO versus Jam‐a WT mice. Surprisingly, in LysM‐cre; Jam‐a fl/fl, the number of PMN recruited into the peritoneum was not affected in response to zymosan nor LPS compared to control littermates, indicating that JAM‐A on PMN is not required for infiltration under such conditions. Importantly, intestinal epithelial‐selective loss of JAM‐A resulted in significant reduction of PMN infiltration in Villin‐cre; Jam‐a fl/fl mice, confirming that extrinsic factors, independent on JAM‐A expression on PMN are necessary for leukocyte recruitment to peritoneum under the conditions studied. We also observed that in response to zymosan or LPS, peritoneal macrophages from Jam‐a KO or Villin‐cre; Jam‐a fl/fl mice produced less of the chemokine CXCL1 and had reduced activity of the transcription factor NFkB. Conversely, peritoneal macrophages from LysM‐cre; Jam‐a fl/fl mice were unaffected compared to Jam‐a fl/fl mice. Given that loss of JAM‐A on intestinal epithelial cells resulted in increased intestinal permeability, we hypothesized that bacterial derived products may impair peritoneal macrophage function. Therefore, experiments were conducted with germ free Villin‐cre; Jam‐a fl/fl mice. We observed that macrophage responses as well as peritoneal recruitment of PMN in response to zymosan or LPS was not affected compared to control mice. These findings suggest that a leaky intestinal barrier and intestinal microbes are critical in regulating systemic neutrophil recruitment through effects on macrophage release of inflammatory mediators. Such observations highlight the functional link between the intestinal barrier, microbiota and the regulation of innate immune responses.Support or Funding InformationNIH grants 1R01DK097256 to TLD, DK59888, DK55679 to AN and DK072564, DK061379, and DK079392 to CP.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Polymorphonuclear Neutrophils Play a Decisive Role for Brain Injury and Neurological Recovery Poststroke.

Polymorphonuclear Neutrophils Play a Decisive Role for Brain Injury and Neurological Recovery Poststroke.

CD11b Regulates Fungal Outgrowth but Not Neutrophil Recruitment in a Mouse Model of Invasive Pulmonary Aspergillosis.

ß2 integrin receptors consist of an alpha subunit (CD11a-CD11d) and CD18 as the common beta subunit, and are differentially expressed by leukocytes. ß2 integrins are required for cell-cell interaction, transendothelial migration, uptake of opsonized pathogens, and cell signaling processes. Functional loss of CD18—termed leukocyte-adhesion deficiency type 1 (LAD1)—results in an immunocompromised state characterized by frequent occurrence of severe infections. In immunosuppressed individuals Aspergillus fumigatus is a frequent cause of invasive pulmonary fungal infection, and often occurs in patients suffering from LAD1. Here, we asked for the importance of CD11b/CD18 also termed MAC-1 which is required for phagocytosis of opsonized A. fumigatus conidia by polymorphonuclear neutrophils (PMN) for control of pulmonary A. fumigatus infection. We show that CD11b−/− mice infected with A. fumigatus were unaffected in long term survival, similar to wild type (WT) mice. However, bronchoalveolar lavage (BAL) performed 1 day after infection revealed a higher lung infiltration of PMN in case of infected CD11b−/− mice than observed for WT mice. BAL derived from infected CD11b−/− mice also contained a higher amount of leukocyte-attracting CCL5 chemokine, but lower amounts of proinflammatory innate cytokines. In accordance, lung tissue of A. fumigatus infected CD11b−/− mice was characterized by lower cellular inflammation, and a higher fungal burden. In agreement, CD11b−/−PMN exerted lower phagocytic activity on serum-opsonized A. fumigatus conidia than WT PMN in vitro. Our study shows that MAC-1 is required for effective clearance of A. fumigatus by infiltrating PMN, and the establishment of an inflammatory microenvironment in infected lung. Enhanced infiltration of CD11b−/− PMN may serve to compensate impaired PMN function.

Midkine drives cardiac inflammation by promoting neutrophil trafficking and NETosis in myocarditis.

Heart failure due to dilated cardiomyopathy is frequently caused by myocarditis. However, the pathogenesis of myocarditis remains incompletely understood. Here, we report the presence of neutrophil extracellular traps (NETs) in cardiac tissue of patients and mice with myocarditis. Inhibition of NET formation in experimental autoimmune myocarditis (EAM) of mice substantially reduces inflammation in the acute phase of the disease. Targeting the cytokine midkine (MK), which mediates NET formation in vitro, not only attenuates NET formation in vivo and the infiltration of polymorphonuclear neutrophils (PMNs) but also reduces fibrosis and preserves systolic function during EAM. Low-density lipoprotein receptor-related protein 1 (LRP1) acts as the functionally relevant receptor for MK-induced PMN recruitment as well as NET formation. In summary, NETosis substantially contributes to the pathogenesis of myocarditis and drives cardiac inflammation, probably via MK, which promotes PMN trafficking and NETosis. Thus, MK as well as NETs may represent novel therapeutic targets for the treatment of cardiac inflammation.

Simvastatin Reduces Neutrophils Infiltration Into Brain Parenchyma After Intracerebral Hemorrhage via Regulating Peripheral Neutrophils Apoptosis.

Statins, known for their lipid-lowering effects, also have immunomodulatory properties. This study aims to examine whether systematic simvastatin administration could decrease polymorphonuclear neutrophils (PMNs) infiltration into brain tissue, as well as alleviate neuroinflammation in a rat model of intracerebral hemorrhage (ICH). The ICH model was induced in adult male Sprague–Dawley rats by an injection of autologous blood. Animals randomly received simvastatin (i.p. 2 mg/kg) or vehicle daily from 5 days before ICH until sacrificed. Routine blood counts, brain water content, neurological scoring, immunofluorescence and RT-PCR were conducted to evaluate the anti-inflammatory effect of simvastatin following ICH. Furthermore, flow cytometric and western blotting analysis were implemented for elucidating the mechanisms involved in simvastatin-induced reduction of neutrophil brain-invading. Elevated PMNs count and neutrophil-to-lymphocyte ratio in circulation were detected in rat model of ICH, which was reversed by using simvastatin. Simvastatin effectively alleviated PMNs infiltration and proinflammatory factors release in perihematomal area, as well as attenuated ICH-induced brain edema and neurological deficits. Simvastatin significantly downregulated the expression of antiapoptotic protein-Mcl-1 while increased the level of proapoptotic protein-Bax and cleaved caspase 3 in PMNs. Simvastatin treatment significantly alleviated PMNs brain-infiltrating and subsequent neuroinflammatory reaction after ICH, in part by accelerating peripheral PMNs apoptosis through disorganized the expression of apoptotic related proteins. Our data provided new evidence for simvastatin application on patients with ICH.

NLRP12 promotes host resistance against Pseudomonas aeruginosa keratitis inflammatory responses through the negative regulation of NF-κB signaling.

To investigate the role of NLRP12 in regulating Pseudomonas aeruginosa (P. aeruginosa) keratitis. Real-Time-PCR and Western blot were performed to measure the NLRP12 level in corneas and bone marrow-derived macrophages (BMDMs) of C57BL/6 (B6) mice. B6 mice received a subconjunctival injection of lentivirus expressing active NLRP12 (NLRP12-lentivirus) or Ctl-lentivirus (as control), followed by infection of P. aeruginosa. The clinical score, slit lamp and bacterial plate count of mice were evaluated. In addition, myeloperoxidase (MPO) was detected to assess the infiltration of polymorphonuclear neutrophil (PMN). Cytokine levels were measured by Real Time-PCR and ELISA. Meanwhile, the bacterial burden was also evaluated. The activation of NF-κB signaling was determined by pIκBα/IκBα levels based on Western blot and NF-κB-dependent Luciferase activity on the basis of Luciferase assays using 293T cells. NLRP12 mRNA and protein levels were decreased in B6 corneas and BMDMs after P. aeruginosa infection. The over-expression of NLRP12 in B6 corneas significantly ameliorated the severity of corneal disease, bacterial burden, PMN infiltration and pro-inflammatory cytokine expression. In vitro analysis demonstrated that the up-regulation of NLRP12 suppressed pro-inflammatory cytokine production and enhanced bacterial clearance in RAW264.7 cells. The protein levels of pIκBα and IκBα were significantly decreased after NLRP12-lentivirus treatment compared with that of Ctl-lentivirus. NF-κB-dependent Luciferase activity was potently inhibited by NLRP12 infected with P. aeruginosa or cotransfected with the downstream signaling molecules including IKKα and IKKβ in 293T cells. NLRP12 decreases the severity of P. aeruginosa keratitis, reduces corneal inflammation and bacterial burden through the down-regulation of the NF-κB signaling pathway.

High-Density Infiltration of V-domain Immunoglobulin Suppressor of T-cell Activation Up-regulated Immune Cells in Human Pancreatic Cancer.

We performed immunohistochemistry to determine VISTA expression in human pancreatic cancer samples. We found that 88.46% of the patients showed high-density infiltration of polymorphonuclear neutrophils and mononuclear immune cells with up-regulated expression of VISTA in cancer tissues, especially in the necrotic foci. Interestingly, it was minimally expressed in pancreatic cancerous cells and was not detectable in either normal ducts or islet cells in cancerous or normal pancreatic tissues. We conclude that VISTA is predominantly expressed and up-regulated in the high-density infiltrated immune cells but minimal in human pancreatic cancerous cells. Our results for the first time highlight pancreatic immunosuppressive tumor microenvironment contributed by VISTA and its potential as a prominent target for pancreatic cancer immunotherapy.

Unified nexus of macrophages and maresins in cardiac reparative mechanisms

Macrophages are immune-sensing "big eater" phagocytic cells responsible for an innate, adaptive, and regenerative response. After myocardial infarction, macrophages predominantly clear the deceased cardiomyocyte apoptotic or necrotic neutrophils to develop a regenerative and reparative program with the activation of the lipoxygenase-mediated maresin (MaR) metabolome at the site of ischemic injury. The specialized proresolving molecule and macrophage mediator in resolving inflammation, MaR-1, produced by human macrophages, has potent defining effects that limit polymorphonuclear neutrophil infiltration, enhance uptake of apoptotic PMNs, regulate inflammation resolution and tissue regeneration, and reduce pain. In addition to proresolving and anti-inflammatory actions, MaR-1 displays potent tissue regenerative effects in stroke and is an antinociceptive. Macrophages actively participate in the biosynthesis of bioactive MaR-2, which exhibits anti-inflammatory, proresolving, and atherosclerotic effects. A new class of macrophage-derived molecules, MaR conjugates in tissue regeneration, is identified that regulates phagocytosis and the repair and regeneration of damaged tissue. The presented review provides a current summary of the effect of MaR in resolution pathophysiology, with relevance to a cardiac repair program.-Jadapalli, J. K., Halade, G. V. Unified nexus of macrophages and maresins in cardiac reparative mechanisms.

Pulmonary Effects of Adjusting Tidal Volume to Actual or Ideal Body Weight in Ventilated Obese Mice

Obese patients could be more susceptible to mechanical ventilation (MV)-induced lung injury than non-obese patients due to weight-dependent changes in lung properties. The aim of this study was therefore to evaluate the pulmonary effects of 2 hours low VT MV in a diet-induced obese mice model, with VT calculated on either the actual body weight (VTaw) or the ideal body weight (VTiw) . First, we hypothesized that a MV with VTaw would be associated with altered lung mechanics and an increased lung inflammation. Second, we hypothesised that a MV with a VTiw would preserve lung mechanics and limit lung inflammation. We analyzed lung mechanics and inflammation using bronchoalveolar lavage (BAL) cell counts, flow cytometry tissue analysis and histology. Lung mechanics and inflammation were comparable in control and obese mice receiving VTiw. By contrast, obese mice receiving VTaw had significantly more alterations in lung mechanics, BAL cellularity and lung influx of monocytes as compared to control mice. Their monocyte expression of Gr1 and CD62L was also increased. Alveolar neutrophil infiltration was significantly increased in all obese mice as compared to controls. In conclusion, our findings suggest that protective MV with a VTaw is deleterious, with a marked alteration in lung mechanics and associated lung inflammation as compared to lean mice. With VTiw, lung mechanics and inflammation were close to that of control mice, except for an increased alveolar infiltrate of polymorphonuclear neutrophils. This inflammation might be attenuated by a blunted recruitment of inflammatory cells associated with obesity.

Beneficial Role of Neutrophils Through Function of Lactoferrin After Intracerebral Hemorrhage.

Intracerebral hemorrhage (ICH) is a devastating disease with a 30-day mortality of ~50%. There are no effective therapies for ICH. ICH results in brain damage in 2 major ways: through the mechanical forces of extravasated blood and then through toxicity of the intraparenchymal blood components including hemoglobin/iron. LTF (lactoferrin) is an iron-binding protein, uniquely abundant in polymorphonuclear neutrophils (PMNs). After ICH, circulating blood PMNs enter the ICH-afflicted brain where they release LTF. By virtue of sequestrating iron, LTF may contribute to hematoma detoxification. ICH in mice was produced using intrastriatal autologous blood injection. PMNs were depleted with intraperitoneal administration of anti-Ly-6G antibody. Treatment of mouse brain cell cultures with lysed RBC or iron was used as in vitro model of ICH. LTF mRNA was undetectable in the mouse brain, even after ICH. Unlike mRNA, LTF protein increased in ICH-affected hemispheres by 6 hours, peaked at 24 to 72 hours, and remained elevated for at least a week after ICH. At the single cell level, LTF was detected in PMNs in the hematoma-affected brain at all time points after ICH. We also found elevated LTF in the plasma after ICH, with a temporal profile similar to LTF changes in the brain. Importantly, mrLTF (recombinant mouse LTF) reduced the cytotoxicity of lysed RBC and FeCl3 to brain cells in culture. Ultimately, in an ICH model, systemic administration of mrLTF (at 3, 24, and 48 hours after ICH) reduced brain edema and ameliorated neurological deficits caused by ICH. mrLTF retained the benefit in reducing behavioral deficit even with 24-hour treatment delay. Interestingly, systemic depletion of PMNs at 24 hours after ICH worsened neurological deficits, suggesting that PMN infiltration into the brain at later stages after ICH could be a beneficial response. LTF delivered to the ICH-affected brain by infiltrating PMNs may assist in hematoma detoxification and represent a powerful potential target for the treatment of ICH.

The activity of pomegranate extract standardized 40% ellagic acid during the healing process of incision wounds in albino rats (Rattus norvegicus)

Aim:This research aimed to evaluate the effects of pomegranate extract standardized to 40% ellagic acid on the incised wound in albino rats.Materials and Methods:Fifty albino rats were divided into 10 treatment groups. The five groups were sacrificed on the 8th day, while the others were sacrificed on the 15th day. Two groups of albino rats with incised wound were not treated at all (P0), the other two groups of albino rats with incised wound were treated with Betadine® (P1) ointment, and the rest of the groups were treated with pomegranate extract standardized to 40% ellagic acid with a concentration of 2.5% (P2), 5% (P3), and 7.5% (P4). The treatments were carried out twice a day with an interval of 12 h for 7 and 14 days. At the end of the research, the skin tissue of those albino rats had been taken for histopathologic preparations before H and E staining was performed.Results:Collagen deposition, polymorphonuclear neutrophils (PMN) infiltration, angiogenesis, and fibrosis degree in Group P4 treated with 7.5% pomegranate extract standardized to 40% ellagic acid for 14 days were significantly different from those in Groups P0, P1, P2, and P3, especially in the case of PMN inflammation (p<0.05).Conclusion:The administration of 7.5% pomegranate extract standardized to 40% ellagic acid for 14 days on incised wounds of those albino rats can accelerate the wound healing process characterized by collagen deposition improvement, PMN infiltration in the wound area, angiogenesis, and fibrosis degree.

Changes in the microarchitecture of the pancreatic cancer stroma are linked to neutrophil-dependent reprogramming of stellate cells and reflected by diffusion-weighted magnetic resonance imaging

In pancreatic cancer (PDAC) intratumor infiltration of polymorphonuclear neutrophils (PMN) is associated with histologically apparent alterations of the tumor growth pattern. The aim of this study was to examine possible associations between PMN infiltration, tumor microarchitecture, and water diffusivity in diffusion-weighted magnetic resonance imaging (DW-MRI), and to further asses the underlying mechanisms.Methods: DW-MRI was performed in 33 PDAC patients prior to surgery. In parallel, tissue specimen were examined histologically for growth pattern, azurocidin-positive PMN infiltrates, and the presence of alpha-smooth muscle actin (α-SMA) and metalloproteinase 9 (MMP9)-positive myofibroblastic cells. For confirmation of the histological findings, a tissue microarray of a second cohort of patients (n=109) was prepared and examined similarly. For in vitro studies, the pancreatic stellate cell line RLT was co-cultivated either with isolated PMN, PMN-lysates, or recombinant azurocidin and characterized by Western blot, flow cytometry, and proteome profiler arrays.Results: Tumors with high PMN density showed restricted water diffusion in DW-MRI and histologic apparent alterations of the tumor microarchitecture (microglandular, micropapillary, or overall poorly differentiated growth pattern) as opposed to tumors with scattered PMN. Areas with altered growth pattern lacked α-SMA-positive myofibroblastic cells. Tissue microarrays confirmed a close association of high PMN density with alterations of the tumor microarchitecture and revealed a significant association of high PMN density with poor histologic grade of differentiation (G3). In vitro experiments provided evidence for direct effects of PMN on stellate cells, where a change to a spindle shaped cell morphology in response to PMN and to PMN-derived azurocidin was seen. Azurocidin incorporated into stellate cells, where it associated with F-actin. Down-regulation of α-SMA was seen within hours, as was activation of the p38-cofilin axis, up-regulation of MMP9, and acquisition of intracellular lipid droplets, which together indicate a phenotype switch of the stellate cells.Conclusion: In PDAC, PMN infiltrates are associated with alterations of the tumor microarchitecture. As a causal relationship, we propose a reprogramming of stellate cells by PMN-derived azurocidin towards a phenotype, which affects the microarchitecture of the tumor.

Histopathology in Periprosthetic Joint Infection: When Will the Morphomolecular Diagnosis Be a Reality?

The presence of a polymorphonuclear neutrophil infiltrate in periprosthetic tissues has been shown to correlate closely with the diagnosis of septic implant failure. The histological criterion considered by the Musculoskeletal Infection Society to be diagnostic of periprosthetic joint infection is “greater than five neutrophils per high-power field in five high-power fields observed from histologic analysis of periprosthetic tissue at ×400 magnification.” Surgeons and pathologists should be aware of the qualifications introduced by different authors during the last years in the histological techniques, samples for histological study, cutoffs used for the diagnosis of infection, and types of patients studied. Recently, immunohistochemistry and histochemistry studies have appeared which suggest that the cutoff point of five polymorphonuclear neutrophils in five high-power fields is too high for the diagnosis of many periprosthetic joint infections. Therefore, morphomolecular techniques could help in the future to achieve a more reliable histological diagnosis of periprosthetic joint infection.

Coronin 1A, a novel player in integrin biology, controls neutrophil trafficking in innate immunity

AbstractTrafficking of polymorphonuclear neutrophils (PMNs) during inflammation critically depends on the β2 integrins lymphocyte function–associated antigen 1 (LFA-1) (CD11a/CD18) and macrophage-1 antigen (CD11b/CD18). Here, we identify coronin 1A (Coro1A) as a novel regulator of β2 integrins that interacts with the cytoplasmic tail of CD18 and is crucial for induction of PMN adhesion and postadhesion events, including adhesion strengthening, spreading, and migration under flow conditions. Transition of PMN rolling to firm adhesion critically depends on Coro1A by regulating the accumulation of high-affinity LFA-1 in focal zones of adherent cells. Defective integrin affinity regulation in the genetic absence of Coro1A impairs leukocyte adhesion and extravasation in inflamed cremaster muscle venules in comparison with control animals. In a Helicobacter pylori mouse infection model, PMN infiltration into the gastric mucosa is dramatically reduced in Coro1A−/− mice, resulting in an attenuated gastric inflammation. Thus, Coro1A represents an important novel player in integrin biology, with key functions in PMN trafficking during innate immunity.

A synthetic cationic antimicrobial peptide inhibits inflammatory response and the NLRP3 inflammasome by neutralizing LPS and ATP.

Antimicrobial peptides (AMPs) are one of the most important defense mechanisms against bacterial infections in insects, plants, non-mammalian vertebrates, and mammals. In the present study, a class of synthetic AMPs was evaluated for anti-inflammatory activity. One cationic AMP, GW-A2, demonstrated the ability to inhibit the expression levels of nitric oxide (NO), inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in lipopolysaccharide (LPS)-activated macrophages. GW-A2 reduced LPS-induced increases in the phosphorylation of mitogen-activated protein kinase and protein kinase C-α/δ and the activation of NF-κB. GW-A2 also inhibited NLRP3 inflammasome activation induced by LPS and ATP. Furthermore, in the mice injected with LPS, GW-A2 reduced (1) the concentration of IL-1β, IL-6 and TNF-α in the serum; (2) the concentration of TNF-α in the peritoneal lavage; (3) the expression levels of iNOS, COX-2 and NLRP3 in the liver and lung; (4) the infiltration of polymorphonuclear neutrophils in the liver and lung. The underlying mechanisms for the anti-inflammatory activity of GW-A2 were found to be partially due to LPS and ATP neutralization. These results provide insights into how GW-A2 inhibits inflammation and the NLRP3 inflammasome and provide a foundation for the design of rational therapeutics for inflammation-related diseases.

Osteopontin facilitates West Nile virus neuroinvasion via neutrophil \u201cTrojan horse\u201d transport

West Nile virus (WNV) can cause severe human neurological diseases including encephalitis and meningitis. The mechanisms by which WNV enters the central nervous system (CNS) and host-factors that are involved in WNV neuroinvasion are not completely understood. The proinflammatory chemokine osteopontin (OPN) is induced in multiple neuroinflammatory diseases and is responsible for leukocyte recruitment to sites of its expression. In this study, we found that WNV infection induced OPN expression in both human and mouse cells. Interestingly, WNV-infected OPN deficient (Opn−/−) mice exhibited a higher survival rate (70%) than wild type (WT) control mice (30%), suggesting OPN plays a deleterious role in WNV infection. Despite comparable levels of viral load in circulating blood cells and peripheral organs in the two groups, WNV-infected polymorphonuclear neutrophil (PMN) infiltration and viral burden in brain of Opn−/− mice were significantly lower than in WT mice. Importantly, intracerebral administration of recombinant OPN into the brains of Opn−/− mice resulted in increased WNV-infected PMN infiltration and viral burden in the brain, which was coupled to increased mortality. The overall results suggest that OPN facilitates WNV neuroinvasion by recruiting WNV-infected PMNs into the brain.