Neutrophil Chemotactic Activity Research Articles

Exosomal secreted SCIMP regulates communication between macrophages and neutrophils in pneumonia

In pneumonia, the deficient or delayed pathogen clearance can lead to pathogen proliferation and subsequent overactive immune responses, inducing acute lung injury (ALI). While screening human genome coding genes using our peripheral blood cell chemotactic platform, we unexpectedly find SLP adaptor and CSK interacting membrane protein (SCIMP), a protein with neutrophil chemotactic activity secreted during ALI. However, the specific role of SCIMP in ALI remains unclear. In this study, we investigate the secretion of SCIMP in exosomes (SCIMPexo) by macrophages after bacterial stimulation, both in vitro and in vivo. We observe a significant increase in the levels of SCIMPexo in bronchoalveolar lavage fluid and serum of pneumonia patients. We also find that bronchial perfusion with SCIMPexo or SCIMP N-terminal peptides increases the survival rate of the ALI model. This occurs due to the chemoattraction and activation of peripheral neutrophils dependent on formyl peptide receptor 1/2 (FPR1/2). Conversely, exosome suppressors and FPR1/2 antagonists decrease the survival rate in the lethal ALI model. Scimp-deficient and Fpr1/2-deficient mice also have lower survival rates and shorter survival times than wild-type mice. However, bronchial perfusion of SCIMP rescues Scimp-deficient mice but not Fpr1/2-deficient mice. Collectively, our findings suggest that the macrophage-SCIMP-FPRs-neutrophil axis plays a vital role in the innate immune process underlying ALI.

Store-operated calcium entry enhances the polarization and chemotaxis of neutrophils in the peripheral venous blood of patients with bronchial asthma by upregulating ERM protein.

Neutrophils can be rapidly recruited and are largely abundant in the airways of patients with asthma. However, whether the polarization and chemotaxis of neutrophils in patients with asthma are abnormal, and the underlying mechanisms, have not been clarified. Pseudopods formation is the initial step of neutrophils' polarization, ezrin, radixin and moesin (ERM) play an important role in the polarization of neutrophils. As an important signaling molecule in cell physiological processes, Ca2+ has been shown to be involved in the polarity changes of neutrophils. This study thus aimed to explore polarization and chemotaxis of neutrophils in patients with asthma and the underlying mechanism. Fresh neutrophils were isolated using standard separation protocols. The polarization and chemotactic activity of neutrophils were observed using Zigmond chamber and Transwell migration assay under linear concentration gradients of N-formyl-methionine-leucine-phenylalanine (fMLP) or interleukin (IL)-8. The distribution of calcium, ERMs and F-actin in neutrophils were observed by confocal laser scanning microscope. The expression of the main components of ERMs (moesin and ezrin) was detected with reverse transcription-polymerase chain reaction (RT-PCR). Compared with those in the healthy control group, the polarization and chemotaxis of neutrophils in the venous blood of patients with asthma were significantly increased, and the expression and distribution of cytoskeletal proteins F-actin and ezrin were abnormal. The expression and function of key components of store-operated calcium entry (SOCE), stromal interaction molecule 1 (STIM1), STIM2, and Orai1 of neutrophils in patients with asthma were significantly increased. The polarization and chemotaxis of neutrophils in the venous blood of patients with asthma are increased. This may be due to the abnormal expression and distribution of ERM and F-actin as a result of abnormal SOCE function.

Ketamine or propofol anesthesia in dogs: how do they affect cytokines, antioxidants and neutrophil functions?

The objective of the study is to investigate the effects of ketamine and propofol on cytokines, antioxidant defense system, and neutrophil functions in dogs. A total of 24 dogs were used. Dogs were divided into two groups as ketamine and propofol. The ketamine group received ketamine (5 mg/kg) intravenously while the propofol group received propofol (4 mg/kg) intravenously. Blood samples were collected before sedation and 30 minutes after induction. Serum antioxidant and cytokine levels were analyzed and neutrophil functions were determined. Respiration rate, serum malondialdehyde, IL-4, IL-6 levels, and phagocytic and chemotaxic activity of neutrophils were decreased (P=0.001, P=0.010, P=0.014, P=0.039, P=0.008, and P=0.037, respectively), oxygen saturation were increased (P=0.025) in the ketamine group. Serum IL-6 and IFN-γ level were decreased (P=0.015 and P=0.032 respectively), chemotactic activity of neutrophils were increased (P=0.049) in propofol group. The administration of ketamine was found to have a positive effect both on the antioxidant system and the neutrophil. On the other hand, positive and negative effects of propofol on different parts of the immune system were observed. Therefore, the results should should be taken into account when designing an anesthesia protocol for dogs to predict possible defense system reactions during the postoperative period.

Identification of N-formylated Peptides with Neutrophilic Chemotactic Activity in Mycobacterium tuberculosis

Neutrophil infiltration of the lungs is associated with granuloma formation and the severity of tuberculosis infection. Although several cytokines and chemokines are known to contribute to lung neutrophil infiltration, the neutrophilic chemotactic factors of Mycobacterium tuberculosis (Mtb) remain unexplored. Therefore, we performed Transwell based chemotactic assays using neutrophils from human peripheral blood and mouse bone marrow to probe the chemotactic activity of the culture filtrates (CF) of Mtb H37Rv. CF of H37Rv induced chemotaxis of both human and mouse neutrophils, and this was also confirmed with CF of 9 clinical isolates and Erdman strain of Mtb with neutrophil chemotactic activity. Sulfasalazine, an N-formyl-Met-Leu-Phe (fMLF) receptor inhibitor, blocked the chemotaxis of neutrophils induced by CF of Mtb, thus indicating the involvement of the fMLF receptor in Mtb CF induced chemotaxis of neutrophils. Mass spectrometry analysis of CF of H37Rv identified three candidate N-formylated heptapeptides. The chemotactic activity of the identified peptides was confirmed with their synthetic mimetics that they induced neutrophil chemotaxis in a manner dependent on N-terminal formylation. For all formylated peptides and CF of Mtb, the induced Ca2+ influx in neutrophils was suppressed by sulfasalazine. Thus, we identified novel formylated Mtb peptides with neutrophil chemotactic activity.

Bovine viral diarrhea virus compromises Neutrophil's functions in strain dependent manner

Bovine viral diarrhea virus (BVDV) infection is a major problem that results in economically important diseases of the cattle industry worldwide. The two major consequences of this disease are persistent infection and immune dysfunction. A number of studies have been done to determine the underline mechanisms of BVDV-induced immune dysfunction, in particular targeting antigen-presenting cells, T- and B- cells and cytokine gene expression. However, little research has focused Eon the effect of BVDV on neutrophils. Neutrophils are one of the predominant leukocytes circulating in blood and are considered the first line of defense in the innate immune system along with macrophages. Neutrophils not only eliminate the invading bacteria but also activate innate as well as adaptive immune responses. Therefore, compromised neutrophil function would affect both arms of immune system and caused immune suppression. In the current study, we used virus strains from both BVDV-1 and BVDV-2 species. Including a highly virulent non-cytopathic type 2a BVDV (ncp BVDV2a-1373), moderately virulent non-cytopathic type 2a (ncp BVDV2a 28508-5), and a pair of non-cytopathic type 1b BVDV (ncp BVDV1b TGAN) and cytopathic type 1b BVDV (cp BVDV1b TGAC) strain isolated from a case of mucosal disease. The highly virulent ncp BVDV2a-1373 significantly increased neutrophil apoptosis. However, none of the other BVDV strains affected neutrophil viability. All BVDV strains used significantly reduced CD18 and L-selectin expression on neutrophils as well as their oxidative burst and neutrophil extracellular traps (NET) activity. Cp BVDV significantly reduced neutrophil's phagocytic activity but ncp BVDV did not have any effect on it. On the other hand, ncp BVDV significantly increased neutrophil's CD14 expression and chemotactic activity while cp BVDV did not show any effect either on neutrophil's CD14 expression or on chemotactic activity. In conclusion, BVDV affected neutrophils variability and functional activity in strain dependent manner. Results of the current study will further help in understanding the pathophysiology of different BVDV strains.

Biological Characterization of Commercial Recombinantly Expressed Immunomodulating Proteins Contaminated with Bacterial Products in the Year 2020: The SAA3 Case.

The serum amyloid A (SAA) gene family is highly conserved and encodes acute phase proteins that are upregulated in response to inflammatory triggers. Over the years, a considerable amount of literature has been published attributing a wide range of biological effects to SAAs such as leukocyte recruitment, cytokine and chemokine expression and induction of matrix metalloproteinases. Furthermore, SAAs have also been linked to protumorigenic, proatherogenic and anti-inflammatory effects. Here, we investigated the biological effects conveyed by murine SAA3 (mu rSAA3) recombinantly expressed in Escherichia coli. We observed the upregulation of a number of chemokines including CCL2, CCL3, CXCL1, CXCL2, CXCL6 or CXCL8 following stimulation of monocytic, fibroblastoid and peritoneal cells with mu rSAA3. Furthermore, this SAA variant displayed potent in vivo recruitment of neutrophils through the activation of TLR4. However, a major problem associated with proteins derived from recombinant expression in bacteria is potential contamination with various bacterial products, such as lipopolysaccharide, lipoproteins and formylated peptides. This is of particular relevance in the case of SAA as there currently exists a discrepancy in biological activity between SAA derived from recombinant expression and that of an endogenous source, i.e. inflammatory plasma. Therefore, we subjected commercial recombinant mu rSAA3 to purification to homogeneity via reversed-phase high-performance liquid chromatography (RP-HPLC) and re-assessed its biological potential. RP-HPLC-purified mu rSAA3 did not induce chemokines and lacked in vivo neutrophil chemotactic activity, but retained the capacity to synergize with CXCL8 in the activation of neutrophils. In conclusion, experimental results obtained when using proteins recombinantly expressed in bacteria should always be interpreted with care.

Identification of N-formylated peptides as the neutrophilic chemotactic factors of Mycobacterium tuberculosis

Abstract Since tuberculosis (TB) remains a major cause of human death, it is urgent to understand the pathology of TB. Lung neutrophil infiltration initiates granuloma formation and is associated with disease severity. Though several cytokines and chemokines are associated with neutrophil infiltration in chronic inflammation, neutrophil chemotactic factors of Mycobacterium tuberculosis (Mtb) remain unexplored. Thus, we performed neutrophil chemotactic assays by culturing neutrophils of healthy human blood samples and mouse bone marrow in the upper chamber of a transwell plate with 5–8 μm pores with the culture filtrates of Mtb H37Rv (CF) in the lower chamber using N-formyl-met-leu-phe (fMLF), a bacterial neutrophil chemotactic tripeptide, as a positive control. The cell numbers in the lower chamber were determined by flow cytometry as a chemotactic indicator. Our results show that CF induced chemotaxis of both human and mouse neutrophils in an Mtb culture period dependent manner. Testing CF of 11 clinical isolates of Mtb also showed neutrophil chemotactic activity. Sulfasalazine, a formylated peptide receptor inhibitor, blocked chemotaxis of neutrophils, indicating the involvement of fPRs in CF induces chemotaxis of neutrophils. Mass spectrometry analysis of CF identified three candidate N-formylated heptapeptides. Authentication of the chemotactic activities of the identified peptides with synthetic mimetics confirmed their neutrophil chemotactic activities and indicated the requirement of N-formylation for their chemotactic activities. Thus, we have identified novel formylated peptides of Mtb with neutrophil chemotactic activities, and further studies are in progress to determine their significance in TB infection.

Are Chemokines IL-8 (CXCL8) and MCP-1 (Monocyte Chemoatractant 1) Cooperating to Enhance Inflammation in Children with Sickle Cell Disease Living in Sub-Saharan area?

1. Introduction ickle cell disease is a genetic disease very prevalent in the world and particularly in Sub-Saharan African countries. The prevalence ranges from 20% and 30%. In some African countries, it can reach 45% [1]. The number of newborns affected by this genetic disease is estimated at 240,000 per year or 0.3 to 25 per 1000 live births with fifty to seventy five percentages who do not reach the age of five [2–4]. In Côte d’Ivoire, country located in west Africa, the SCD prevalence rate is 12% [5]. As such, SCD is one of the greatest public health treat of all time and represent a public health problem. This disease makes patients more vulnerable to infections with high mortality, organs damage, and chronic anemia among children [6]. A better comprehension of the disease physiopathology in general will help to develop therapeutic approach to improve the management of the patients. There is an ongoing regular inflammatory status due to high levels of cytokines [7]. In this course, chemokines CXL and CCL also have been identified participating in this inflammatory process, particularly Interleukin-8 (IL8 or CXCL-8) and Monocyte Chemoattractant Protein-1, (MCP-1or CCL2). These two chemokines have been identified as having a chemotactic activity for neutrophils, monocytes, macrophages and lymphocytes [8]. Detection of inflammatory cytokines in the during non-crisis periods could be a guide for medical to improve management of SCD patients. This study strives to observe whether chemokines IL-8 and MCP-1 can be used to predict morbidity or mortality in SCD children.

A novel bovine CXCL15 gene in the GRO chemokine gene cluster

In our previous transcriptomic studies using DNA microarray analysis, a probe designed from an unknown expressed sequence tag (EST) showed significant differential gene expression in the pharyngeal epithelia. The objectives of this study are to annotate the gene sequence and compare the gene transcription levels among different bovine tissues based on our published microarray data. The gene transcribing the EST contains a 90-amino-acid protein sequence. The results of bioinformatic analyses using comparative genetics, multiple sequence alignments, phylogenetic analysis and promoter sequence analysis indicated that this gene is a novel ELR+ CXCL gene orthologous to mouse CXCL15. The gene is highly conserved in ruminants and exists in many other mammals but not in chickens, primates or pigs. Phylogenetic analysis and gene structures showed that CXCL15 is closer to CXCL8 than to other ELR+ CXCLs. Our microarray data show that bovine CXCL15 expression was higher in laser capture micro-dissected bovine pharyngeal epithelia than in the whole pharyngeal tissues, which agrees with the expression in mice. However, unlike the high expression in the mouse lung, our results showed that the bovine nasal turbinate, dorsal nasopharynx, dorsal soft palate and tongue expressed higher levels of CXCL15 than the lung and skins. Promoter analysis showed that ruminants have more immune-related transcription factor binding sites in the proximal promoters of CXCL15 than mouse. CXCL15 has previously only been reported in mice and has neutrophil chemotactic activity. Given the critical roles of neutrophils in innate immunity, this study provides useful information for further characterization of bovine CXCL15.

Effect of mite allergenic components on innate immune response: Synergy of protease (Group 1 & 3) and non-protease (Group 2 & 7) allergens

The major mite allergenic components of protease allergens (group 1,3) and non-protease allergens (group 2,7) derived from Dermatophagoides peronyssinus (Dp) and D. farinae (Df) are reported to be capable of sensitizing 80–90% of mite–allergic patients. Although protease and non-protease allergens have been demonstrated to trigger innate and adaptive immune responses through epithelium activation, the simultaneous or sequential effects of both groups of allergens has not been reported. Since all allergens are present in the mite crude extracts, it is important to determine whether these allergens can synergistically trigger the immune responses to cause airway inflammation. A total of 60 house dust mite (HDM)-allergic asthmatic patients were recruited to analyze their serum-specific IgE response to both groups of allergens. Recombinant protease allergen (Der p1 and Der p3) and non-protease allergens (Der p2 and Der p7) were used to activate the human airway epithelium cell (Beas-2B). The cells were analyzed for mRNA expression of IL-6/IL-8 and the culture supernatants were analyzed for neutrophil chemotactic activity (NCA). The results showed 48/60 (80%) HDM-allergic patients were sensitized to all allergenic components of Der p1, Der p2, Der f1, and Der f2. Most of the allergic patients were sensitized to both groups of allergens simultaneously. The associations of Der p1 with Der p2 were 83.3% (50/60) and Der f1 with Der f2 were 80% (48/60). When Beas-2B cells were cultured with Der p2 in conjunction with Der p1 and Der p3, the results showed that there was increased expression of IL-6/IL-8 in comparison with culture with allergen alone. There was only a trivial effect on IL-6/IL-8 expression when Der p2 was co-cultured with Der p7. Similar findings were obtained in the NCA measurement. When Beas-2B was cultured with Der p2 in conjunction with Der p1 and Der p3, there was increased NCA in comparison with culture with allergen alone. There were also trivial effects when Der p2 was co-cultured with Der p7. The allergens (Der p2 and Der p3)-induced IL-6/IL-8 expression and NCA released from Beas-2B could be downregulated by dexamethasone and transcription factor inhibitor SP600125. The allergenic components derived from Dp and Df can sensitize allergic patients simultaneously and activate epithelium through protease allergens (group 1, 3) and non-protease allergen (group 2) synergistically.

Feasibility and physiological relevance of designing highly potent aminopeptidase-sparing leukotriene A4 hydrolase inhibitors

Leukotriene A4 Hydrolase (LTA4H) is a bifunctional zinc metalloenzyme that comprises both epoxide hydrolase and aminopeptidase activity, exerted by two overlapping catalytic sites. The epoxide hydrolase function of the enzyme catalyzes the biosynthesis of the pro-inflammatory lipid mediator leukotriene (LT) B4. Recent literature suggests that the aminopeptidase function of LTA4H is responsible for degradation of the tripeptide Pro-Gly-Pro (PGP) for which neutrophil chemotactic activity has been postulated. It has been speculated that the design of epoxide hydrolase selective LTA4H inhibitors that spare the aminopeptidase pocket may therefore lead to more efficacious anti-inflammatory drugs. In this study, we conducted a high throughput screen (HTS) for LTA4H inhibitors and attempted to rationally design compounds that would spare the PGP degrading function. While we were able to identify compounds with preference for the epoxide hydrolase function, absolute selectivity was not achievable for highly potent compounds. In order to assess the relevance of designing such aminopeptidase-sparing LTA4H inhibitors, we studied the role of PGP in inducing inflammation in different settings in wild type and LTA4H deficient (LTA4H KO) animals but could not confirm its chemotactic potential. Attempting to design highly potent epoxide hydrolase selective LTA4H inhibitors, therefore seems to be neither feasible nor relevant.

Renal Sodium Gradient Orchestrates a Dynamic Antibacterial Defense Zone

Lower urinary tract infections are among the most common human bacterial infections, but extension to the kidneys is rare. This has been attributed to mechanical forces, such as urine flow, that prevent the ascent of bladder microbes. Here, we show that the regional hypersalinity, required for the kidney's urine-concentrating function, instructs epithelial cells to produce chemokines that localize monocyte-derived mononuclear phagocytes (MNPs) to the medulla. This hypersaline environment also increases the intrinsic bactericidal and neutrophil chemotactic activities of MNPs to generate a zone of defense. Because MNP positioning and function are dynamically regulated by the renal salt gradient, we find that patients with urinary concentrating defects are susceptible to kidney infection. Our work reveals a critical accessory role for the homeostatic function of a vital organ in optimizing tissue defense.

Gemcitabine-generated ROS promotes neutrophil chemotactic activity through CXCL8 production via PKCδ/ERK pathway in a murine 4T1 breast cancer model

Abstract Chemotherapy-induced neutropenia (CIN) is a common side effect that necessitate dose reductions during treatment of cancer patients. Preventing CIN is critical in chemotherapy because a rapid decline of neutrophil counts increase susceptibility to infection of cancer patients. In spite of its importance, the mechanism of CIN still remains unclear. This study is aimed to investigate the mechanism of CIN in an aspect of neutrophil activation by chemotaxis in gemcitabine-treated breast tumor model. We hypothesized that gemcitabine-generated ROS promotes CXCL8 or MIP-2 production by upregulating ERK pathway in PKCδ-activated intratumoral macrophages and thus neutrophil recruitment to the chemokine gradient. In 4T1 breast tumor mouse model, we found that the basal level of PKCδ activity was higher than in normal mice. The number of blood and peritoneal leukocytes was analyzed at 24h after intraperitoneal administration of gemcitabine. The neutrophil counts decreased in the blood but increased in the peritoneal cavity. In addition, intratumoral neutrophils were elevated in the gemcitabine-treated group. The mRNA levels of neutrophil attracting chemokines/receptors were increased in the peritoneal and tumoral cells. ROS inhibitors N-Acetyl-L-cysteine and Apocynin blocked gemcitabine-induced neutrophil migration, mRNA expression of the chemokines and receptors and PKCδ/ERK phosphorylation. CXCR1/2 inhibitor reparixin decreased neutrophil recruitment to the peritoneal cavity and the tumor tissue. Together, our results suggest that gemcitabine treatment promotes neutrophil chemotactic activity by increasing ROS/PKCδ/ERK/CXCL8 pathway. These findings will provide new insights for developing a therapeutic for CIN.

A Critical Role for P2X7 Receptor-Induced VCAM-1 Shedding and Neutrophil Infiltration during Acute Lung Injury.

Pulmonary neutrophils are the initial inflammatory cells that are recruited during lung injury and are crucial for innate immunity. However, pathological recruitment of neutrophils results in lung injury. The objective of this study is to determine whether the novel neutrophil chemoattractant, soluble VCAM-1 (sVCAM-1), recruits pathological levels of neutrophils to injury sites and amplifies lung inflammation during acute lung injury. The mice with P2X7 receptor deficiency, or treated with a P2X7 receptor inhibitor or anti-VCAM-1 Abs, were subjected to a clinically relevant two-hit LPS and mechanical ventilation-induced acute lung injury. Neutrophil infiltration and lung inflammation were measured. Neutrophil chemotactic activities were determined by a chemotaxis assay. VCAM-1 shedding and signaling pathways were assessed in isolated lung epithelial cells. Ab neutralization of sVCAM-1 or deficiency or antagonism of P2X7R reduced neutrophil infiltration and proinflammatory cytokine levels. The ligands for sVCAM-1 were increased during acute lung injury. sVCAM-1 had neutrophil chemotactic activities and activated alveolar macrophages. VCAM-1 is released into the alveolar airspace from alveolar epithelial type I cells through P2X7 receptor-mediated activation of the metalloproteinase ADAM-17. In conclusion, sVCAM-1 is a novel chemoattractant for neutrophils and an activator for alveolar macrophages. Targeting sVCAM-1 provides a therapeutic intervention that could block pathological neutrophil recruitment, without interfering with the physiological recruitment of neutrophils, thus avoiding the impairment of host defenses.

Immunological attributes of blood and milk neutrophils isolated from crossbred cows during different physiological conditions

The goal of this work was to understand how polymorphonuclear leukocytes (PMN), the first line of cellular defence, integrate and prioritize multiple chemotactic signals to navigate during periods of demand like subclinical mastitis (SCM), clinical mastitis (CM), pregnancy (P), and calving (C). For this, blood and milk samples were collected from five groups of crossbred cows (healthy, with SCM, CM, pregnant, and newly calved). Maximum viability was seen in the PMN of healthy cows, whereas minimum viability was observed in CM cows. Phagocytic activity (PA) of blood and milk PMN decreased significantly (P < 0.05) at C and in CM cows. Chemotactic activity of blood PMN was minimum in C followed by CM, SCM, and P cows. PA was found to be negatively correlated with the plasma cortisol levels and inverse relationship was observed between the plasma interleukin-8 (IL-8) levels and the chemotactic activity of neutrophils. There was a significantly (P < 0.05) higher expression of CXCR1 and IL-8 on both blood and milk PMN of CM cows followed by C and SCM cows. Minimum expression of selectin (CD-62L) was seen on blood PMN isolated around calving, whereas maximum expression of integrin (CD-11b) was in CM cows. Healthy and P cows showed the highest expression of CD-62L on blood PMN but its expression remained unaltered in milk PMN. Irrespective of physiological stage of the cows, immune suppression was found to be always cortisol dependent. Observing the neutrophil activity and mRNA expression of genes isolated from cow neutrophils can be used as indicators to assess the health/physiological status promptly for immediate therapeutic or management-related actions.

Immunomodulatory activity of Apis mellifera propolis from the North of Argentina

Propolis is a bee hive product with complex chemical composition that was used as medicine from ancient times. The immunomodulatory activity of partially purified propolis extracts (PPPEs), galangin and pinocembrin was studied through their in vitro effect on neutrophil chemotactic and phagocytic activities. PPPEs (15 samples from each of 10 different beehives) were more effective (around 45% and 50% for a concentration of 40 μg of PPPEs/mL of active substance) as chemotactic agents than galangin and pinocembrin (around 20 and 25%, respectively) and showed higher neutrophil phagocitic activity (270 ± 10% for beehive 10) than galangin and pinocembrin (180 ± 10 and 135 ± 9%, respectively). The highest effect of PPPEs can be attributed to a synergistic effect among components of PPPEs. The results of this study indicated that PPPEs, galangin and pinocembrin stimulate neutrophil chemotactic activity at various concentrations suggesting their possible use for patients suffering neutrophil disfunction. The nitro blue tetrazolium results indicated that the extracts and isolated flavonoids have the capacity to scavenge active radicals suggesting that they would be valuable in the treatment of diseases associated with free radical damage.Consequently, the in vitro results suggest a potential value of these propolis extracts in the medical field.

Isolation of Terpenoids from the Stem of Ficus aurantiaca Griff and their Effects on Reactive Oxygen Species Production and Chemotactic Activity of Neutrophils.

Three new triterpenoids; namely 28,28,30-trihydroxylupeol (1); 3,21,21,26-tetrahydroxy-lanostanoic acid (2) and dehydroxybetulinic acid (3) and seven known compounds; i.e., taraxerone (4); taraxerol (5); ethyl palmitate (6); herniarin (7); stigmasterol (8); ursolic acid (9) and acetyl ursolic acid (10) were isolated from the stem of Ficus aurantiaca Griff. The structures of the compounds were established by spectroscopic techniques. The compounds were evaluated for their inhibitory effects on polymorphonuclear leukocyte (PMN) chemotaxis by using the Boyden chamber technique and on human whole blood and neutrophil reactive oxygen species (ROS) production by using a luminol-based chemiluminescence assay. Among the compounds tested, compounds 1–4, 6 and 9 exhibited strong inhibition of PMN migration towards the chemoattractant N-formyl-methionyl-leucyl-phenylalanine (fMLP) with IC50 values of 6.8; 2.8; 2.5; 4.1; 3.7 and 3.6 μM, respectively, comparable to that of the positive control ibuprofen (6.7 μM). Compounds 2–4, 6, 7 and 9 exhibited strong inhibition of ROS production of PMNs with IC50 values of 0.9; 0.9; 1.3; 1.1; 0.5 and 0.8 μM, respectively, which were lower than that of aspirin (9.4 μM). The bioactive compounds might be potential lead molecules for the development of new immunomodulatory agents to modulate the innate immune response of phagocytes.

The Positively Charged COOH-terminal Glycosaminoglycan-binding CXCL9(74–103) Peptide Inhibits CXCL8-induced Neutrophil Extravasation and Monosodium Urate Crystal-induced Gout in Mice

The ELR(-)CXC chemokine CXCL9 is characterized by a long, highly positively charged COOH-terminal region, absent in most other chemokines. Several natural leukocyte- and fibroblast-derived COOH-terminally truncated CXCL9 forms missing up to 30 amino acids were identified. To investigate the role of the COOH-terminal region of CXCL9, several COOH-terminal peptides were chemically synthesized. These peptides display high affinity for glycosaminoglycans (GAGs) and compete with functional intact chemokines for GAG binding, the longest peptide (CXCL9(74-103)) being the most potent. The COOH-terminal peptide CXCL9(74-103) does not signal through or act as an antagonist for CXCR3, the G protein-coupled CXCL9 receptor, and does not influence neutrophil chemotactic activity of CXCL8 in vitro. Based on the GAG binding data, an anti-inflammatory role for CXCL9(74-103) was further evidenced in vivo. Simultaneous intravenous injection of CXCL9(74-103) with CXCL8 injection in the joint diminished CXCL8-induced neutrophil extravasation. Analogously, monosodium urate crystal-induced neutrophil migration to the tibiofemural articulation, a murine model of gout, is highly reduced by intravenous injection of CXCL9(74-103). These data show that chemokine-derived peptides with high affinity for GAGs may be used as anti-inflammatory peptides; by competing with active chemokines for binding and immobilization on GAGs, these peptides may lower chemokine presentation on the endothelium and disrupt the generation of a chemokine gradient, thereby preventing a chemokine from properly performing its chemotactic function. The CXCL9 peptide may serve as a lead molecule for further development of inhibitors of inflammation based on interference with chemokine-GAG interactions.

Cyclic stretch augments production of neutrophil chemokines, matrix metalloproteinases, and activin a in human endometrial stromal cells.

The aim of this study was to test our hypothesis: Contractile activity that occurs in the uterus during menstruation induces biochemical factors that enhance remodeling of the endometrium. Cyclic stretch, mimicking contractile activity during menstruation, was applied to human endometrial stromal cells (ESC) using the Flexercell Tension system. The concentration and activity of CXCL8, CXCL1, MMPs, and activin A were measured using ELISAs and specific assays. Neutrophil chemotactic activity was evaluated using migration assays. Cyclic stretch significantly induced ESC secretion of CXCL8 and CXCL1 and neutrophil chemotaxis. Stretch also increased MMP-1, MMP-2, and MMP-3 activity, activin A secretion, and activity in ESC. These results indicate that the contractile activities of the uterus during menstruation contribute to the remodeling of the endometrium, by inducing chemokine secretion, MMP expression, activity, and neutrophil chemotaxis.

Expression Profile of CXCL3 Gene in Peripheral Blood Mononuclear Cells Challengedin vitrowithTheileria annulatain Crossbred Cattle

Bovine tropical theileriosis is a major haemoprotozoan disease associated with high rates of morbidity and mortality particularly in exotic and crossbred cattle. Recent studies suggest that a number of immune response genes, expressed differentially in exotic and indigenous breeds play an important role in breed specific resistance to tropical theileriosis. In the present study, expression of CXCL3 gene which has chemotactic activity for neutrophils, controls migration and adhesion of monocytes and ultimately mediates its effects on target cells by interacting with a cell surface chemokine receptor called CXCR2 was studied in crossbred cattle. The in vitro experimental result revealed significant difference in CXCL3 gene expression in Theileria annulata challenged peripheral blood mononuclear cells of crossbred animals as compared to healthy controls and a 2.53 fold increase (p < 0.05) was recorded. The results of current study indicate that CXCL3 may be involved in host-pathogen interaction during tropical theileriosis.