Tissue Neutrophil Accumulation Research Articles

Selenoproteome depletion enhances oxidative stress and alters neutrophil functions in Citrobacter rodentium infection leading to gastrointestinal inflammation.

Reactive oxygen species (ROS) play a critical role in modulating a range of proinflammatory functions in neutrophils, as well as regulating neutrophil apoptosis and facilitating the resolution of an inflammatory response. Selenoproteins with the 21st amino acid, selenocysteine (Sec), regulate the immune mechanisms through the modulation of the redox homeostasis aiding in the efficient resolution of inflammation, while their role in neutrophil functions during diseases remains unclear. To study the role of selenoproteins in neutrophils during infection, we challenged the granulocyte-specific tRNASec (Trsp) knockout mice (TrspN) with Citrobacter rodentium (C. rodentium), a murine pathogenic bacterium. Reduced bacterial shedding during the disease-clearing phase and increased tissue damage and neutrophil accumulation in the colon of the TrspN mice were observed following infection. TrspN neutrophils showed increased intracellular ROS accumulation during ex vivo C. rodentium stimulation and upregulated fMLP-induced chemotaxis. We also observed delayed neutrophil apoptosis, reduced efferocytosis of TrspN neutrophils, and increased abundance of apoptotic cells in the colon of TrspN mice. Together, these studies indicate that selenoprotein depletion results in increased neutrophil migration to the gut accompanied by ROS accumulation, while downregulating neutrophil apoptosis and subsequent efferocytosis by macrophages. Such an increase in inflammation followed by impaired resolution culminates in decreased bacterial load but with exacerbated host tissue damage.

Immunoproteasomal Inhibition With ONX-0914 Attenuates Atherosclerosis and Reduces White Adipose Tissue Mass and Metabolic Syndrome in Mice.

Atherosclerosis is the major underlying pathology of cardiovascular disease and is driven by dyslipidemia and inflammation. Inhibition of the immunoproteasome, a proteasome variant that is predominantly expressed by immune cells and plays an important role in antigen presentation, has been shown to have immunosuppressive effects. We assessed the effect of ONX-0914, an inhibitor of the immunoproteasomal catalytic subunits LMP7 (proteasome subunit β5i/large multifunctional peptidase 7) and LMP2 (proteasome subunit β1i/large multifunctional peptidase 2), on atherosclerosis and metabolism in LDLr-/- and APOE*3-Leiden.CETP mice. ONX-0914 treatment significantly reduced atherosclerosis, reduced dendritic cell and macrophage levels and their activation, as well as the levels of antigen-experienced T cells during early plaque formation, and Th1 cells in advanced atherosclerosis in young and aged mice in various immune compartments. Additionally, ONX-0914 treatment led to a strong reduction in white adipose tissue mass and adipocyte progenitors, which coincided with neutrophil and macrophage accumulation in white adipose tissue. ONX-0914 reduced intestinal triglyceride uptake and gastric emptying, likely contributing to the reduction in white adipose tissue mass, as ONX-0914 did not increase energy expenditure or reduce total food intake. Concomitant with the reduction in white adipose tissue mass upon ONX-0914 treatment, we observed improvements in markers of metabolic syndrome, including lowered plasma triglyceride levels, insulin levels, and fasting blood glucose. We propose that immunoproteasomal inhibition reduces 3 major causes underlying cardiovascular disease, dyslipidemia, metabolic syndrome, and inflammation and is a new target in drug development for atherosclerosis treatment.

GLUT1 Promotes NLRP3 Inflammasome Activation of Airway Epithelium in Lipopolysaccharide-Induced Acute Lung Injury

Acute lung injury (ALI) is a devastating clinical disease caused by different factors, with high morbidity and mortality. It has been shown that lung injury and inflammation caused by lipopolysaccharide (LPS) can be modulated by NLRP3 inflammasome activation, yet its exact function within the airway epithelium is still unknown. Meanwhile, glucose transporter protein 1 (GLUT1) has been shown to contribute to a number of inflammatory illnesses, including ALI. The present study was aimed to assess GLUT1's function in NLRP3 inflammasome activation of airway epithelium in LPS-induced acute lung injury. BALB/c mice (5 mg/kg) and BEAS-2B cells (200 μg/mL) were respectively exposed to LPS, with or without GLUT1 antagonists (WZB117 or BAY876). LPS upregulated pulmonary expression of NLRP3 and GLUT1 in mice, which could be blocked by WZB117 or BAY876. Pharmacological inhibition of GLUT1 in vivo significantly attenuated lung tissue damage, neutrophil accumulation, and proinflammatory factors release (TNF-α, IL-6, and IL-1β) in LPS-exposed mice. Meanwhile, the activation markers of NLRP3 inflammasome (ASC, caspase-1, IL-1β, and IL-18) induced by LPS were also suppressed. In cultured BEAS-2B cells, LPS induced an increase in GLUT1 expression and triggers activation of the NLRP3 inflammasome, both of which were inhibited by GLUT1 antagonists. These results illustrated that GLUT1 participates in LPS-induced ALI, and promotes the activation of the NLRP3 inflammasome in airway epithelial cells.

Post-COVID syndrome: clinical presentations and therapeutic approaches

The article presents a literature review on the pathogenesis, clinical and radiological manifestations and therapy options for post-COVID syndrome. The pathophysiological mechanisms underlying lung injury in severe COVID-19 and ARDS of any other aetiology include acute injury to the alveolar epithelium and pulmonary vascular endothelium with increased alveolar-capillary permeability, interstitial and alveolar oedema, formation of hyaluronic membranes, and accumulation of neutrophils in the lung tissue. The completion of the acute phase is followed by hyperplasia of type II alveolocytes, proliferation of fibroblasts and myofibroblasts as manifestations of the reparative processes. Post-COVID syndrome combines pathological conditions that are accompanied by the clinically meaningful decline in quality of life and risk of death and persist for a long time after the disappearance of the infectious symptoms of the disease. Post-COVID lung parenchymal consolidations are accompanied by impaired pulmonary ventilation, frequent development of chronic respiratory failure with exercise-induced hypoxemia, reduce the patients’ quality of life and require treatment. Currently, attempts are being made to use various drugs for the treatment of post-COVID interstitial changes in lungs, but the evidence base for providing guidelines is currently insufficient. Bovhyaluronidase azoximer is one of the promising drugs. A multicenter, randomized, double-blind, placebo-controlled, parallel-group clinical trial to evaluate the efficacy of bovhyaluronidase azoximer in patients with post-covid interstitial changes in lungs is currently being conducted in the Russian Federation. The study results can provide reliable information about the place and role of this drug in the treatment of post-COVID interstitial changes in lungs.

Erythromycin Restores Osteoblast Differentiation and Osteogenesis Suppressed by Porphyromonas gingivalis Lipopolysaccharide.

The macrolide erythromycin (ERM) inhibits excessive neutrophil accumulation and bone resorption in inflammatory tissues. We previously reported that the expression of developmental endothelial locus-1 (DEL-1), an endogenous anti-inflammatory factor induced by ERM, is involved in ERM action. Furthermore, DEL-1 is involved in the induction of bone regeneration. Therefore, in this study, we investigated whether ERM exerts an osteoblastogenic effect by upregulating DEL-1 under inflammatory conditions. We performed in vitro cell-based mechanistic analyses and used a model of Porphyromonas gingivalis lipopolysaccharide (LPS)-induced periodontitis to evaluate how ERM restores osteoblast activity. In vitro, P. gingivalis LPS stimulation suppressed osteoblast differentiation and bone formation. However, ERM treatment combined with P. gingivalis LPS stimulation upregulated osteoblast differentiation-related factors and Del1, indicating that osteoblast differentiation was restored. Alveolar bone resorption and gene expression were evaluated in a periodontitis model, and the results confirmed that ERM treatment increased DEL-1 expression and suppressed bone loss by increasing the expression of osteoblast-associated factors. In conclusion, ERM restores bone metabolism homeostasis in inflammatory environments possibly via the induction of DEL-1.

High-Dose Mycobacterium tuberculosis H37rv Infection in IL-17A- and IL-17A/F-Deficient Mice.

During experimental tuberculosis (TB), interleukin (IL)-17A appears to be involved in the formation of lung granulomas, possibly through the attraction of neutrophils to the sites of infection. However, the protective impact of cytokine appears to depend on the degree of its induction. Hence, robust production of IL-17A in mice infected with the hypervirulent isolate Mycobacterium tuberculosis (Mtb) HN878 mediates protection, while the cytokine is dispensable for protective immune responses against low-dose infection with the less virulent strain H37rv. Here, we show that after experimental infection with high doses of Mtb H37rv, IL-17A-deficient (−/−) mice exhibited high susceptibility to the infection, which was mediated by the strong accumulation of neutrophils in the infected lung tissue. Accordingly, we observed nearly unrestricted bacterial replication within the neutrophils, indicating that they may serve as a survival niche for Mtb. By use of IL-17A/IL-17F-double-deficient mice, we demonstrated that the susceptibility in the absence of IL-17A is mediated by a compensatory expression of IL-17F, which, however, appeared not to be dependent on neutrophils. Together, our results illustrate the compensatory potential of the Th17-secreted cytokines IL-17A and IL-17F in the context of experimental TB and once again emphasize the detrimental effect of excessive neutrophil infiltration in response to Mtb.

Observation of Curative Effect of Lung Recruitment in Patients with Acute Respiratory Distress Syndrome after Cardiopulmonary Bypass Surgery.

Recruitment maneuver (RM) has become a routine supplementary maneuver for clinical rescue of severe ARDS with low tidal volume/pressure-limited mechanical ventilation. Recruitment of patients with ARDS mechanical ventilation can improve the lung compliance, promote the opening of collapsed alveoli, improve the ratio of ventilation to blood flow, reduce dead space, reduce shunt flow, and improve oxygenation function. In this paper, the patients were divided into lung recruitment group and conventional treatment group by the random number permutation table method. When the patient's percutaneous oxygen saturation is less than or equal to 88%, the partial pressure of oxygen in the arterial blood gas is less than or equal to 55 mmHg, or the ventilator tube is disconnected during sputum suction or other accidents, a CPAP × 60 − second lung recruitment maneuver is required. Then adjust the ventilator parameters in the same way. In the process of lung recruitment, the changes in invasive continuous arterial blood pressure will also be observed. If the blood pressure dropped to ≤90/60 mmHg, one recruitment maneuver was terminated in advance. And both groups of patients used the Dräger- or PB840-imported multifunctional ventilator. The treatment of primary disease and predisposing factors, fluid management strategies, antibiotics and glucocorticoids, nutrition, and metabolic support in the two groups of patients in the study were the same. The PaO2/FiO2 value improved by 51% 10 minutes after recruitment, and the median increased from 111 (IQR, 73-265) before recruitment to 170 (IQR, 102-340) (P < 0.01), the improvement of PaO2/FiO2 at 4 hours after recruitment and 12 hours after recruitment was 78% (P < 0.05) and 39% (P < 0.01), respectively, and the median PaO2/FiO2 at 4 hours after recruitment was 198 (IQR, 116-256). The median PaO2/FiO2 became 155 (IQR, 127-235) 12 hours after recruitment. Recruitment can reduce the accumulation of neutrophils in lung tissue, reduce the release of inflammatory factors, reduce pulmonary edema, and reduce pathological damage.

IsoLGs (Isolevuglandins) Drive Neutrophil Migration in Hypertension and Are Essential for the Formation of Neutrophil Extracellular Traps.

IsoLGs (isolevuglandins) are electrophilic products of lipid peroxidation formed in the presence of reactive oxygen species. IsoLGs contribute to hypertension by an unknown mechanism. Studies have shown that reactive oxygen species production drives the formation of neutrophil extracellular traps (NETs) and that NETs accumulate within the aorta and kidneys of patients with hypertension. The purpose of this study was to determine the role of isoLGs in neutrophil migration and NET formation (NETosis) in hypertension. Mice were treated with Ang II (angiotensin II) and the specific isoLG scavenger 2-hydroxybenzylamine and examined for tissue neutrophil and NET accumulation by single-cell sequencing and flow cytometry. Isolated human neutrophils were studied to determine the role of isoLGs in NETosis and neutrophil chromatin expansion by immunofluorescence and live cell confocal microscopy. Single-cell sequencing performed on sham, Ang II, and Ang II+2-hydroxybenzylamine treated mice revealed neutrophils as a primary target of 2-hydroxybenzylamine. Peripheral neutrophil migration, aortic NET accumulation, and renal NET accumulation is blocked with 2-hydroxybenzylamine treatment. In isolated human neutrophils, isoLGs accumulate during NETosis and scavenging of isoLGs prevents NETosis. IsoLGs drive neutrophil chromatin expansion during NETosis and disrupt nucleosome structure. These observations identified a critical role of isoLGs in neutrophil migration and NETosis in hypertension and provide a potential therapy for NET-associated diseases including hypertension and associated end organ damage.

Apolipoprotein Mimetic Peptide Inhibits Neutrophil-Driven Inflammatory Damage via Membrane Remodeling and Suppression of Cell Lysis.

Neutrophils are crucial for host defense but are notorious for causing sterile inflammatory damage. Activated neutrophils in inflamed tissue can liberate histone H4, which was recently shown to perpetuate inflammation by permeating membranes via the generation of negative Gaussian curvature (NGC), leading to lytic cell death. Here, we show that it is possible to build peptides or proteins that cancel NGC in membranes and thereby suppress pore formation, and demonstrate that they can inhibit H4 membrane remodeling and thereby reduce histone H4-driven lytic cell death and resultant inflammation. As a demonstration of principle, we use apolipoprotein A-I (apoA-I) mimetic peptide apoMP1. X-ray structural studies and theoretical calculations show that apoMP1 induces nanoscopic positive Gaussian curvature (PGC), which interacts with the NGC induced by the N-terminus of histone H4 (H4n) to inhibit membrane permeation. Interestingly, we show that induction of PGC can inhibit membrane-permeating activity in general and "turn off" diverse membrane-permeating molecules besides H4n. In vitro experiments show an apoMP1 dose-dependent rescue of H4 cytotoxicity. Using a mouse model, we show that tissue accumulation of neutrophils, release of neutrophil extracellular traps (NETs), and extracellular H4 all strongly correlate independently with local tissue cell death in multiple organs, but administration of apoMP1 inhibits histone H4-mediated cytotoxicity and strongly prevents organ tissue damage.

Interleukin-1α Is a Central Regulator of Leukocyte-Endothelial Adhesion in Myocardial Infarction and in Chronic Kidney Disease.

Cardiovascular diseases and chronic kidney disease (CKD) are highly prevalent, aggravate each other, and account for substantial mortality. Both conditions are characterized by activation of the innate immune system. The alarmin interleukin-1α (IL-1α) is expressed in a variety of cell types promoting (sterile) systemic inflammation. The aim of the present study was to examine the role of IL-1α in mediating inflammation in the setting of acute myocardial infarction (AMI) and CKD. We assessed the expression of IL-1α on the surface of monocytes from patients with AMI and patients with CKD and determined its association with atherosclerotic cardiovascular disease events during follow-up in an explorative clinical study. Furthermore, we assessed the inflammatory effects of IL-1α in several organ injury models in Il1a-/- and Il1b-/- mice and investigated the underlying mechanisms in vitro in monocytes and endothelial cells. IL-1α is strongly expressed on the surface of monocytes from patients with AMI and CKD compared with healthy controls. Higher IL-1α surface expression on monocytes from patients with AMI and CKD was associated with a higher risk for atherosclerotic cardiovascular disease events, which underlines the clinical relevance of IL-1α. In mice, IL-1α, but not IL-1β, mediates leukocyte-endothelial adhesion as determined by intravital microscopy. IL-1α promotes accumulation of macrophages and neutrophils in inflamed tissue in vivo. Furthermore, IL-1α on monocytes stimulates their homing at sites of vascular injury. A variety of stimuli such as free fatty acids or oxalate crystals induce IL-1α surface expression and release by monocytes, which then mediates their adhesion to the endothelium via IL-1 receptor-1. IL-1α also promotes expression of the VCAM-1 (vascular cell adhesion molecule-1) on endothelial cells, thereby fostering the adhesion of circulating leukocytes. IL-1α induces inflammatory injury after experimental AMI, and abrogation of IL-1α prevents the development of CKD in oxalate or adenine-fed mice. IL-1α represents a key mediator of leukocyte-endothelial adhesion and inflammation in AMI and CKD. Inhibition of IL-1α may serve as a novel anti-inflammatory treatment strategy.

Released Myeloperoxidase Attenuates Neutrophil Migration and Accumulation in Inflamed Tissue.

Neutrophil (PMN) recruitment to sites of insult is critical for host defense, however excessive PMN activity and tissue accumulation can lead to exacerbated inflammation and injury. Myeloperoxidase (MPO) is a PMN azurophilic granule enzyme, which together with H2O2, forms a powerful antimicrobial system designed to kill ingested bacteria. Intriguingly, in addition to intracellular killing of invading microorganisms and extracellular tissue damage due generation of ROS, soluble MPO has been directly implicated in modulating cellular responses and tissue homeostasis. In the current work, we used several models of inflammation, murine and human PMNs and state-of-the-art intravital microscopy to examine the effect of MPO on PMN migration and tissue accumulation. We found that in the absence of functional MPO (MPO knockout, KO mice) inflammatory PMN tissue accumulation was significantly enhanced. We determined that the elevated numbers of PMNs in MPO knockout mice was not due to enhanced viability, but due to increased migratory ability. Acute PMN migration in models of zymosan-induced peritonitis or ligated intestinal loops induced by intraluminal administration of PMN-chemokine CXCL1 was increased over 2-fold in MPO KO compared to wild type (WT) mice. Using real-time intravital imaging of inflamed mouse cremaster muscle and ex vivo PMN co-culture with inflamed endothelial cells (ECs) we demonstrate that elevated migration of MPO KO mice was due to enhanced adhesive interactions. In contrast, addition of soluble recombinant MPO both in vivo and ex vivo diminished PMN adhesion and migration. Although MPO has been previously suggested to bind CD11b, we found no significant difference in CD11b expression in either resting or activated PMNs and further showed that the MPO binding to the PMN surface is not specific to CD11b. As such, our data identify MPO as a novel regulator of PMN trafficking in inflammation.

Agonist anti-ChemR23 mAb reduces tissue neutrophil accumulation and triggers chronic inflammation resolution.

Resolution of inflammation is elicited by proresolving lipids, which activate GPCRs to induce neutrophil apoptosis, reduce neutrophil tissue recruitment, and promote macrophage efferocytosis. Transcriptional analyses in up to 300 patients with Inflammatory Bowel Disease (IBD) identified potential therapeutic targets mediating chronic inflammation. We found that ChemR23, a GPCR targeted by resolvin E1, is overexpressed in inflamed colon tissues of severe IBD patients unresponsive to anti-TNFα or anti-α4β7 therapies and associated with significant mucosal neutrophil accumulation. We also identified an anti-ChemR23 agonist antibody that induces receptor signaling, promotes macrophage efferocytosis, and reduces neutrophil apoptosis at the site of inflammation. This ChemR23 mAb accelerated acute inflammation resolution and triggered resolution in ongoing chronic colitis models, with a significant decrease in tissue lesions, fibrosis and inflammation-driven tumors. Our findings suggest that failure of current IBD therapies may be associated with neutrophil infiltration and that ChemR23 is a promising therapeutic target for chronic inflammation.

1700-P: Exogenous a1-Antitrypsin A Enhances Insulin Sensitivity in Mice Fed a High-Fat Diet by Attenuation of Neutrophil Infiltration in Epididymal Fat

Neutrophil elastase (NE) is a serine protease expressed by neutrophils which is inhibited endogenously by α1-Antitrypsin A (AAT). Obesity is associated with increased plasma NE:AAT ratios and adipose tissue NE accumulation, which may drive obesity-associated metabolic dysfunction. Exogenous AAT is now an FDA approved treatment for AAT deficiency, therefore we investigated whether AAT treatment may also have potential therapeutic benefits for diet induced metabolic dysfunction. Standard Chow and high-fat diet (HFD) fed male C57Bl6 mice were randomized to receive 3x weekly IP injections of either AAT (2mg) or vehicle (PBS) for 10 weeks. Chow fed mice treated with recombinant AAT showed no differences in plasma NE, body weight or metabolic phenotype compared to vehicle treated control mice. However, during HFD feeding AAT treatment attenuated increases in plasma NE and white adipose tissue (WAT) NE and neutrophil accumulation without affecting circulatory neutrophil levels or body weight. Consistent with NE knockout mice being partially protected from HFD glucose intolerance, treatment of HFD fed mice with AAT enhanced whole body insulin sensitivity which was attributed to higher insulin-dependent p-AktSer473 and reduced inflammation markers in WAT but no other peripheral tissues. Treatment of 3T3L1 adipocytes with recombinant NE impaired insulin-stimulated glucose uptake andp-AktSer473, suggesting that inhibition of NE in WAT is the primary mechanism through which AAT treatment enhances insulin sensitivity. Collectively, our data suggests AAT may play a potential role in mitigating diet-induced neutrophil infiltration in WAT insulin resistance. Disclosure R.F. D’Souza: None. J.S.T. Woodhead: None. S.W. Masson: None. S.L. James: None. C. Hedges: None. T.L. Merry: None. Funding Health Research Council of New Zealand

Glycolytic activation of monocytes regulates the accumulation and function of neutrophils in human hepatocellular carcinoma

Neutrophils are one of the most abundant components in human hepatocellular carcinoma (HCC) and have been shown to play important roles in regulating disease progression. However, neutrophils are very short-lived cells in circulation, and mechanisms regulating their accumulation and functions in HCC are not yet fully understood. Monocytes were purified from non-tumor or paired tumor tissues of patients with HCC, and their production of neutrophil-attracting chemokines was evaluated. Mechanisms regulating the expression of CXCL2/8 by tumor monocytes, and the role of tumor monocyte-derived chemokines and cytokines in modulating neutrophil accumulation and functions were studied with both exvivo analyses and invitro experiments. Monocyte-derived CXCL2 and CXCL8 were major factors in regulating the recruitment of neutrophils into tumor milieus. These chemokines, in addition to tumor-derived soluble factors, could inhibit apoptosis and sustain survival of neutrophils, thus leading to neutrophil accumulation in tumor tissues. Moreover, monocyte-derived TNF-α acted synergistically with tumor-derived soluble factors to induce the production of the pro-metastasis factor OSM by neutrophils. Further, the glycolytic switch in tumor-infiltrating monocytes mediated their production of CXCL2 and CXCL8 via the PFKFB3-NF-κB signaling pathway. Accordingly, levels of PFKFB3, CXCL2/CXCL8 production in monocytes and infiltration of OSM-producing neutrophils were positively correlated in human HCC tissues. Our results unveiled a previously unappreciated link between monocytes and neutrophils in human HCC, identifying possible targets that could be therapeutically exploited in the future. Neutrophils constitute a major but poorly understood component of human hepatocellular carcinoma (HCC). Herein, we unveil a novel mechanism by which metabolic switching in monocytes promotes the accumulation of neutrophilsin the tumors of patients with HCC. Both monocyte-produced chemokines and signals from the tumor microenvironment promote the production of the pro-metastatic factor OSM by neutrophils. These data identify potential targets for immune-based anticancer therapies for HCC.

Andrographolide ameliorates oxidative stress, inflammation and histological outcome in complete Freund's adjuvant-induced arthritis

ObjectivesAs one of the main active ingredients of Chinese herbal medicine Andrographis paniculate, andrographolide is used in domestic clinical treatment for respiratory infections and inflammation. This study was designed to investigate the effects of andrographolide as an antioxidant on the level of oxidative stress, neutrophil accumulation and infiltration in joints and synovial tissue of arthritis rats induced by complete freund's adjuvant. MethodsA rat model of rheumatoid arthritis was induced by subcutaneous injection of complete Freund's adjuvant in the footpad. The model was established 14 days after induction. The treatment was performed from 14th day to 35th day with different doses of andrographolide (25, 50, 100 mg/kg) and positive control methotrexate (3 mg/kg).The effects of andrographolide on oxidative stress, neutrophil accumulation and infiltration were measured by the paw swelling, arthritis score, the hot plate test, biochemical analysis, and histology. ResultsThe medium and high-dose andrographolide (50, 100 mg/kg) group declined the levels of tumor necrosis factor-α, interleukin-6 and CXC chemokine ligand2, articular elastase and myeloperoxidase, and increased the levels of antioxidant enzymes superoxide dismutase, catalase, and glutathione. The activity of malondialdehyde and nitrite/nitrate in andrographolide (50, 100 mg/kg) group was weakened than the model group. The degree of swelling and arthritis score of andrographolide group was lower than the model group. The results of hot plate test showed that high dose of andrographolide significantly improved the anti-injury ability of rats; Radiological and histological results showed that the joint osteoporosis, inflammatory cell infiltration, synovial hyperplasia and other phenomena in the andrographolide group were significantly improved. ConclusionsAndrographolide acts as a protective agent for the treatment of complete freund's adjuvant induced rheumatoid arthritis by inhibiting lipid peroxidation and nitrite/nitrate levels in a dose-dependent manner, enhancing antioxidant enzyme activity, reducing levels of chemokines and inflammatory factors, preventing neutrophil accumulation and infiltration.

The Vitamin D Binding Protein and Inflammatory Injury: A Mediator or Sentinel of Tissue Damage?

Neutrophils are the most abundant type of white blood cell in most mammals including humans. The primary role of these cells is host defense against microbes and clearance of tissue debris in order to facilitate wound healing and tissue regeneration. The recruitment of neutrophils from blood into tissues is a key step in this process and is mediated by numerous different chemoattractants. The neutrophil migratory response is essential for host defense and survival, but excessive tissue accumulation of neutrophils is observed in many inflammatory disorders and strongly correlates with disease pathology. The vitamin D binding protein (DBP) is a circulating multifunctional plasma protein that can significantly enhance the chemotactic activity of neutrophil chemoattractants both in vitro and in vivo. Recent in vivo studies using DBP deficient mice showed that DBP plays a larger and more central role during inflammation since it induces selective recruitment of neutrophils, and this cofactor function is not restricted to C5a, as prior in vitro studies indicated, but can enhance chemotaxis to many chemoattractants. DBP also is an extracellular scavenger for actin released from damaged/dead cells and formation of DBP-actin complexes is an immediate host response to tissue injury. Recent in vitro evidence indicates that DBP bound to G-actin, and not free DBP, functions as an indirect but essential cofactor for neutrophil migration. DBP-actin complexes always will be formed regardless of what initiated an inflammation, since release of actin from damaged cells is a common feature in all types of injury and DBP is abundant and ubiquitous in all extracellular fluids. Indeed, these complexes have been detected in blood and tissue fluids from both humans and experimental animals following various forms of injury. The published data strongly supports the premise that DBP-actin complexes are the functional neutrophil chemotactic cofactor that enhances neutrophil chemotaxis in vitro and augments neutrophilic inflammation in vivo. This review will assess the fundamental role of DBP in neutrophilic inflammation and injury.

Mesenchymal Stem Cell-Conditioned Medium Induces Neutrophil Apoptosis Associated with Inhibition of the NF-κB Pathway in Endotoxin-Induced Acute Lung Injury.

The immunomodulatory effects of mesenchymal stem cells (MSCs) are established. However, the effects of MSCs on neutrophil survival in acute lung injury (ALI) remain unclear. The goal of this study was to investigate the effect of an MSC-conditioned medium (MSC-CM) on neutrophil apoptosis in endotoxin-induced ALI. In this study, an MSC-CM was delivered via tail vein injection to wild-type male C57BL/6 mice 4 h after an intratracheal injection of lipopolysaccharide (LPS). Twenty-four hours later, bronchoalveolar lavage fluid (BALF) and lung tissue were collected to perform histology, immunohistochemistry, apoptosis assay of neutrophil, enzyme-linked immunosorbent assays, and an electrophoretic mobility shift assay. Human neutrophils were also collected from patients with sepsis-induced acute respiratory distress syndrome (ARDS). Human neutrophils were treated in vitro with LPS, with or without subsequent MSC-CM co-treatment, and were then analyzed. Administration of the MSC-CM resulted in a significant attenuation of histopathological changes, the levels of interleukin-6 and macrophage inflammatory protein 2, and neutrophil accumulation in mouse lung tissues of LPS-induced ALI. Additionally, MSC-CM therapy enhanced the apoptosis of BALF neutrophils and reduced the expression of the anti-apoptotic molecules, Bcl-xL and Mcl-1, both in vivo and in vitro experiments. Furthermore, phosphorylated and total levels of nuclear factor (NF)-κB p65 were reduced in lung tissues from LPS + MSC-CM mice. Human MSC-CM also reduced the activity levels of NF-κB and matrix metalloproteinase-9 in the human neutrophils from ARDS patients. Thus, the results of this study suggest that the MSC-CM attenuated LPS-induced ALI by inducing neutrophil apoptosis, associated with inhibition of the NF-κB pathway.

Physicochemical and pharmacological evaluation of carvedilol-eudragit® RS100 electrosprayed nanostructures.

Objective(s):This study was carried out to boost the pharmacologic influence of carvedilol (CAR) (as a poorly water-soluble drug) by developing CAR-eudragit® RS100 (Eud) nanofibers and nanobeads benefiting an electrospraying approach. Materials and Methods:CAR-Eud nanoformulations with varying ratios (1:5 and 1:10) at total solution concentrations of 10 %, 15 % and 20 % w/v were formulated. Results:The solution concentration remarkably impressed the size and morphology of the samples; in which, the nanobeads (mean diameter of 135.83 nm) were formed at low solution concentrations and high concentrations led to nanofibers (mean diameter of 193.45 nm) formation. DSC thermographs and PXRD patterns along with FTIR spectrum precisely showed CAR amorphization and no probable chemical interactions between CAR and Eud in the electrosprayed nanosystems. The in vitro release considerations demonstrated that the nanoformulations with the drug: polymer ratios of 1:10 and 1:5 depict rapid dissolution rate compared to the physical mixtures (PMs) and the pure drug. The in vivo studies in Wistar male rats suggested that the electrosprayed nanoformulation (1:10; 20 %) reduced the isoproterenol (ISO) induced elevation of heart rate, necrosis and accumulation of neutrophils in the heart tissue more efficient than the pure drug and PM. Conclusion:Our finding illustrated that the electrospraying as a profitable one-step procedure could be productively benefited to improve the physicochemical features and pharmacologic influences of CAR.

Increased mucosal neutrophil survival is associated with altered microbiota in HIV infection.

Gastrointestinal (GI) mucosal dysfunction predicts and likely contributes to non-infectious comorbidities and mortality in HIV infection and persists despite antiretroviral therapy. However, the mechanisms underlying this dysfunction remain incompletely understood. Neutrophils are important for containment of pathogens but can also contribute to tissue damage due to their release of reactive oxygen species and other potentially harmful effector molecules. Here we used a flow cytometry approach to investigate increased neutrophil lifespan as a mechanism for GI neutrophil accumulation in chronic, treated HIV infection and a potential role for gastrointestinal dysbiosis. We report that increased neutrophil survival contributes to neutrophil accumulation in colorectal biopsy tissue, thus implicating neutrophil lifespan as a new therapeutic target for mucosal inflammation in HIV infection. Additionally, we characterized the intestinal microbiome of colorectal biopsies using 16S rRNA sequencing. We found that a reduced Lactobacillus: Prevotella ratio associated with neutrophil survival, suggesting that intestinal bacteria may contribute to GI neutrophil accumulation in treated HIV infection. Finally, we provide evidence that Lactobacillus species uniquely decrease neutrophil survival and neutrophil frequency in vitro, which could have important therapeutic implications for reducing neutrophil-driven inflammation in HIV and other chronic inflammatory conditions.

L-PGDS-derived PGD2 attenuates acute lung injury by enhancing endothelial barrier formation.

Acute lung injury (ALI) is caused by various stimuli such as acid aspiration and infection, resulting in severe clinical outcomes with high mortality. Prostaglandin D2 (PGD2 ) is a lipid mediator produced in the lungs of patients with ALI. There are two prostaglandin D synthases (PGDS), namely, lipocalin-type PGDS (L-PGDS) and hematopoietic PGDS (H-PGDS). We previously reported the anti-inflammatory role of H-PGDS-derived PGD2 in an endotoxin-induced murine ALI model. Therefore, in this study, we investigated the role of L-PGDS-derived PGD2 in ALI in comparison to H-PGDS-derived PGD2 . Intratracheal administration of HCl caused lung inflammation accompanied by tissue edema and neutrophil accumulation in mouse lungs. The deficiency of both L-PGDS and H-PGDS exacerbated HCl-induced lung dysfunction to a similar extent. Furthermore, a detailed investigation revealed that L-PGDS-derived PGD2 inhibited lung edema, while H-PGDS-derived PGD2 inhibited neutrophil infiltration. Immunostaining showed that inflamed endothelial/epithelial cells express L-PGDS, while macrophages and neutrophils express H-PGDS. Hematopoietic reconstitution with WT bone marrow did not rescue the exacerbated lung edema in L-PGDS deficient mice, indicating the importance of nonhematopoietic endothelial/epithelial cell-expressing L-PGDS for protection against ALI. A modified Miles assay showed that L-PGDS deficiency accelerated vascular hyper-permeability in the inflamed lung, which was suppressed by the stimulation of D prostanoid (DP) receptor, a PGD2 receptor. In vitro, DP agonism enhanced the barrier function of endothelial cells but not epithelial cells. Taken together, our results suggest that in the HCl-induced murine ALI model PGD2 was produced locally by inflamed endothelial and epithelial L-PGDS and this enhanced the endothelial barrier through the DP receptor. Copyright © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.