Neutrophil Activation Responses Research Articles

Quantitative urinary proteome analysis reveals potential biomarkers for disease activity of Behcet’s disease uveitis

PurposeBehçet’s disease-associated uveitis (BDU) is a severe, recurrent inflammatory condition affecting the eye and is part of a systemic vasculitis with unknown etiology, making biomarker discovery essential for disease management. In this study, we intend to investigate potential urinary biomarkers to monitor the disease activity of BDU.MethodsFirstly, label-free data-dependent acquisition (DDA) and tandem mass tag (TMT)-labeled quantitative proteomics methods were used to profile the proteomes of urine from active and quiescent BDU patients, respectively. For further exploration, the remaining fifty urine samples were analyzed by a data-independent acquisition (DIA) quantitative proteomics method.ResultsTwenty-nine and 21 differential proteins were identified in the same urine from BDU patients by label-free DDA and TMT-labeled analyses, respectively. Seventy-nine differentially expressed proteins (DEPs) were significantly changed in other active BDU urine samples compared to those in quiescent BDU urine samples by IDA analysis. Gene Ontology (GO) and protein-protein interaction (PPI) analyses revealed that the DEPs were associated with multiple functions, including the immune and neutrophil activation responses. Finally, seven proteins were identified as candidate biomarkers for BDU monitoring and recurrence prediction, namely, CD38, KCRB, DPP4, FUCA2, MTPN, S100A8 and S100A9.ConclusionsOur results showed that urine can be a good source of biomarkers for BDU. These dysregulated proteins provide potential urinary biomarkers for BDU activity monitoring and provide valuable clues for the analysis of the pathogenic mechanisms of BDU.

PSII-3 Sheep Neutrophil Activation in Response to Garlic in Vitro

Abstract St. Croix hair sheep are known to resist parasitic infection. Parasitic resistance is in part due to the increased number and ability of neutrophil leukocytes to fight pathogens. Dietary supplements such as garlic (Allium sativum L.) are antimicrobial immune modulators that can enhance production. This study sought to evaluate the impact of fresh filtered garlic on sheep neutrophils through In vitro treatment. The study collected blood from the jugular vein of five clinically healthy female St. Croix sheep at NC A&T State University Farm and isolated neutrophils from 10 mL whole blood samples from each animal. The neutrophils were treated with fresh filtered garlic after the total cell count was measured, and 1 million cells were taken for treatment. The total protein concentration in the neutrophil supernatant was measured before and after treatment. Garlic (10 ug/mL PBS) was added to neutrophils, incubated (30 minutes, 37 °C) and centrifuged. Total RNA was extracted from the pellet using the TRIZOL RNA Isolation Protocol (Sigma-Aldrich). The RNA concentration and purity were assessed using a Nanodrop Spectrophotometer (Thermo Scientific Inc.). Pooled RNA from each group was used for cDNA synthesis, followed by qPCR analysis of the expression of 84 test genes related to the innate and adaptive immune response (RT2 profiler array) of the host. Total protein concentration in the supernatant was determined using the BCA Assay (Pierce BCA Protein Assay Kit). In vitro treatment with garlic extract resulted in increased total secreted protein concentrations from treated neutrophils, as well as upregulation of 10 genes involved in immune response and downregulation of 4 genes associated with inflammation and immune regulation. The study findings indicate that garlic stimulates gene transcription and protein secretion in neutrophils from St. Croix sheep in vitro. Studies are needed on the possible impacts on neutrophil function and animal response to infection for sustainable use of garlic in animal production.

KLF2 regulates neutrophil activation and thrombosis in cardiac hypertrophy and heart failure progression.

It is widely recognized that inflammation plays a critical role in cardiac hypertrophy and heart failure. However, clinical trials targeting cytokines have shown equivocal effects, indicating the need for a deeper understanding of the precise role of inflammation and inflammatory cells in heart failure. Leukocytes from human subjects and a rodent model of heart failure were characterized by a marked reduction in expression of Klf2 mRNA. Using a mouse model of angiotensin II–induced nonischemic cardiac dysfunction, we showed that neutrophils played an essential role in the pathogenesis and progression of heart failure. Mechanistically, chronic angiotensin II infusion activated a neutrophil KLF2/NETosis pathway that triggered sporadic thrombosis in small myocardial vessels, leading to myocardial hypoxia, cell death, and hypertrophy. Conversely, targeting neutrophils, neutrophil extracellular traps (NETs), or thrombosis ameliorated these pathological changes and preserved cardiac dysfunction. KLF2 regulated neutrophil activation in response to angiotensin II at the molecular level, partly through crosstalk with HIF1 signaling. Taken together, our data implicate neutrophil-mediated immunothrombotic dysregulation as a critical pathogenic mechanism leading to cardiac hypertrophy and heart failure. This neutrophil KLF2-NETosis-thrombosis mechanism underlying chronic heart failure can be exploited for therapeutic gain by therapies targeting neutrophils, NETosis, or thrombosis.

Identifying changes in immune cells and constructing prognostic models using immune-related genes in post-burn immunosuppression.

BackgroundBurn patients are prone to infection as well as immunosuppression, which is a significant cause of death. Currently, there is a lack of prognostic biomarkers for immunosuppression in burn patients. This study was conducted to identify immune-related genes that are prognosis biomarkers in post-burn immunosuppression and potential targets for immunotherapy.MethodsWe downloaded the gene expression profiles and clinical data of 213 burn patients and 79 healthy samples from the Gene Expression Omnibus (GEO) database. Immune infiltration analysis was used to identify the proportion of circulating immune cells. Functional enrichment analyses were carried out to identify immune-related genes that were used to build miRNA-mRNA networks to screen key genes. Next, we carried out correlation analysis between immune cells and key genes that were then used to construct logistic regression models in GSE77791 and were validated in GSE19743. Finally, we determined the expression of key genes in burn patients using quantitative reverse transcription polymerase chain reaction (qRT-PCR).ResultsA total of 745 differently expressed genes were screened out: 299 were up-regulated and 446 were down-regulated. The number of Th-cells (CD4+) decreased while neutrophils increased in burn patients. The enrichment analysis showed that down-regulated genes were enriched in the T-cell activation pathway, while up-regulated genes were enriched in neutrophil activation response in burn patients. We screened out key genes (NFATC2, RORA, and CAMK4) that could be regulated by miRNA. The expression of key genes was related to the proportion of Th-cells (CD4+) and survival, and was an excellent predictor of prognosis in burns with an area under the curve (AUC) value of 0.945. Finally, we determined that NFATC2, RORA, and CAMK4 were down-regulated in burn patients.ConclusionWe found that NFATC2, RORA, and CAMK4 were likely prognostic biomarkers in post-burn immunosuppression and potential immunotherapeutic targets to convert Th-cell dysfunction.

Randialic acid B and tomentosolic acid block formyl peptide receptor 1 in human neutrophils and attenuate psoriasis-like inflammation in vivo

Psoriasis is a long-lasting inflammatory skin disease lacking proper cure. Dysregulated activation of neutrophils is a major pathogenic factor in psoriasis. Formyl peptide receptor 1 (FPR1) triggers neutrophil activation in response to bacteria- or mitochondria-derived N-formyl peptides, but its significance in neutrophilic psoriasis remains unknown. In this study, we discovered two derivatives of ursolic acid, 3β-hydroxyurs-12,18-dien-28-oic acid (randialic acid B, RAB) and 3β-hydroxyurs-12,19-dien-28-oic acid (tomentosolic acid, TA), as FPR1 inhibitors in human neutrophils with ability to suppress psoriatic symptoms in mice. Both RAB and TA, triterpenoids of traditional medicinal plant Ilex kaushue, selectively inhibited reactive oxygen species production, elastase release, and CD11b expression in human neutrophils activated by FPR1, but not non-FPR1 agonists. Importantly, RAB and TA inhibited the binding of N-formyl peptide to FPR1 in human neutrophils, neutrophil-like THP-1 cells, and hFPR1-transfected HEK293 cells, indicating FPR1 antagonism. Moreover, in assays induced by various concentrations of FPR1 agonist, both RAB and TA acted competitively for its binding to the FPR1 receptor. The FPR1-downstream signaling such as Ca2+ mobilisation and activation of Akt and MAPKs was also competitively inhibited. In addition, imiquimod-induced psoriasis-like symptoms, including epidermal hyperplasia, desquamation with scaling, neutrophil skin infiltration, and transepidermal water loss were significantly reduced by both RAB and TA. The results illustrate a possible role of human neutrophils FPR1 receptor in psoriasis-like inflammation. Accordingly, triterpenoids RAB and TA represent novel FPR1 antagonists and exhibit therapeutic potential for treating neutrophilic inflammatory skin diseases.

Interactions Between Neutrophils and Periodontal Pathogens in Late-Onset Periodontitis.

Late-onset periodontitis is associated with a series of inflammatory reactions induced by periodontal pathogens, such as Porphyromonas gingivalis, a keystone pathogen involved in periodontitis. Neutrophils are the most abundant leukocytes in the periodontal pocket/gingival crevice and inflamed periodontal tissues. They form a “wall” between the dental plaque and the junctional epithelium, preventing microbial invasion. The balance between neutrophils and the microbial community is essential to periodontal homeostasis. Excessive activation of neutrophils in response to periodontal pathogens can induce tissue damage and lead to periodontitis persistence. Therefore, illuminating the interactions between neutrophils and periodontal pathogens is critical for progress in the field of periodontitis. The present review aimed to summarize the interactions between neutrophils and periodontal pathogens in late-onset periodontitis, including neutrophil recruitment, neutrophil mechanisms to clear the pathogens, and pathogen strategies to evade neutrophil-mediated elimination of bacteria. The recruitment is a multi-step process, including tethering and rolling, adhesion, crawling, and transmigration. Neutrophils clear the pathogens mainly by phagocytosis, respiratory burst responses, degranulation, and neutrophil extracellular trap (NET) formation. The mechanisms that pathogens activate to evade neutrophil-mediated killing include impairing neutrophil recruitment, preventing phagocytosis, uncoupling killing from inflammation, and resistance to ROS, degranulation products, and NETs.

The effect of acute somatic pain on the killing activity of neutrophils in newborn rats

The immune system is subject to all sorts of influences. Pain is one of them, accompanying an organism’s existence. It is essential to be aware of and account for age-related characteristics of the innate immunity in order to adequately assess their dynamics in ontogenesis. The literature is scarce on the changes to the killing activity of neutrophils occurring in newborns in response to acute pain. The aim of this study was to detect potential changes to the phagocytic activity of neutrophils in response to an algogenic stimulus in newborn rats. The experiments were carried out in 3-5-day-old rats. Two groups were formed: the control group and the main group, in which acute pain was modelled. Blood samples were collected 2, 30–60 and 120–180 minutes after exposure to the algogenic stimulus. The microbicidal activity of neutrophils was measured using a spectrophotometric modification of the spontaneous/stimulated nitroblue tetrazolium (NBT) reduction test. The results were compared using the Mann-Whitney U test. In the first hour following pain modeling, the stimulated NBT reduction test demonstrated an increase in the measured parameters from 71.5 to 87.4 a.u. (р < 0.001); the spontaneous NBT reduction test showed an increase from 50.7 to 58.6 a.u. (p < 0.01) 30 to 60 min after exposure. The most pronounced change of the microbicidal activity coefficient was observed 2 min after pain modeling, increasing from 1.40 to 1.72 a.u (р < 0.001). By the end of the experiment, the measured parameters approximated their initial values. During the analysis, we accounted for the fact that the neutrophil response to the algogenic stimulus was unfolding in the setting of microbial colonization occurring in newborns.

Discovery and Validation of a Novel Neutrophil Activation Marker Associated with Obesity

Obesity is accompanied by low-grade systemic inflammation that etiologically contributes to obesity-induced cardiovascular disease (CVD). Growing evidence supports that neutrophil, the most abundant type of leukocytes in human, is most likely to be the target peripheral leukocyte subtype initiating the inflammatory cascade in obesity. However, few studies have systematically assessed the genome wide changes in neutrophils associated with obesity. In this study, a hypothesis-free OMIC approach (i.e. the discovery phase) and a target approach (i.e. the validation phase) were used to identify obesity related neutrophil activation markers and their roles on CVD risks. In the discovery phase, genome wide DNA methylation, RNA-sequencing and quantitative proteomics were obtained from purified neutrophils (12 obese vs. 12 lean). In the validation phase, gene expression levels of the promising genes from the OMIC platforms were measured in 81 obese cases vs. 83 lean controls, and the association between the expression levels and CVD risks were evaluated. Significant difference was found for one gene, alkaline phosphatase, liver/bone/kidney (ALPL), across 3 OMIC platforms. In the validation phase, the gene expression levels of ALPL in leukocytes were significantly higher in obese compared with lean subjects (p < 0.05). Within the obese population, we observed that ALPL expression level showed significantly positive association with CVD risk factors (p < 0.05) including systolic blood pressure, diastolic blood pressure, mean arterial pressure, carotid intima–media thickness and borderline significance with fasting insulin (p = 0.08). This study identified one novel marker ALPL of neutrophil activation in response to obesity and provided evidence that obesity induced change in ALPL expression was associated with CVD risk factors.

ALPL, A Novel Marker Of Neutrophil Activation In Response To Obesity

Low‐grade systemic inflammation accompanies obesity and etiologically contributes to obesity‐induced cardiovascular disease (CVD). Neutrophils represent the most abundant type of leukocytes in humans and neutrophil activation is a fundamental process in the inflammatory response. Growing evidence supports that neutrophil is most likely to be the target peripheral leukocyte subtype initiating the inflammatory cascade in response to obesity. However, few studies have systematically assessed the molecular changes of neutrophils in response to obesity. In this study, a hypothesis‐free OMIC approach (i.e. the discovery phase) and a target approach (i.e. the validation phase) were used to identify obesity related neutrophil activation markers and their roles on CVD risks. In the discovery phase, genome wide DNA methylation, RNA‐sequencing and quantitative proteomics were obtained from the purified neutrophils of 12 obese cases and 12 lean controls. Significant difference was found for one gene, alkaline phosphatase, liver/bone/kidney (ALPL), across 3 OMIC platforms. In the validation phase, the expression levels of ALPL in leukocytes were obtained from 81 obese cases and 83 lean controls. The ALPL expression levels were significantly higher in obese compared with lean subjects (p=0.021). Within obese population, we observed that ALPL expression level showed significantly positive association with CVD risk factors including systolic blood pressure (BP) (p=0.032), diastolic BP (p=0.011) and mean arterial pressure (p=0.008), as well as borderline significance with fasting insulin (p=0.059). This study identified one novel marker of neutrophil activation in response to obesity and provided further evidence that obesity induced change in ALPL expression is associated with CVD risk factors.Support or Funding InformationNHLBI HL105689This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Neutrophil activation in response to monomeric myeloperoxidase.

Myeloperoxidase (MPO) is an oxidant-producing enzyme that can also regulate cellular functions via its nonenzymatic effects. Mature active MPO isolated from normal human neutrophils is a 145 kDa homodimer, which consists of 2 identical protomers, connected by a single disulfide bond. By binding to CD11b/CD18 integrin, dimeric MPO induces neutrophil activation and adhesion augmenting leukocyte accumulation at sites of inflammation. This study was performed to compare the potency of dimeric and monomeric MPO to elicit selected neutrophil responses. Monomeric MPO (hemi-MPO) was obtained by treating the dimeric MPO by reductive alkylation. Analysis of the crucial signal transducer, intracellular Ca2+, showed that dimeric MPO induces Ca2+ mobilization from the intracellular calcium stores of neutrophils and influx of extracellular Ca2+ whereas the effect of monomeric MPO on Ca2+ increase in neutrophils was less. It was also shown that monomeric MPO was less efficient than dimeric MPO at inducing actin cytoskeleton reorganization, cell survival, and neutrophil degranulation. Furthermore, we have detected monomeric MPO in the blood plasma of patients with acute inflammation. Our data suggest that the decomposition of dimeric MPO into monomers can serve as a regulatory mechanism that controls MPO-dependent activation of neutrophils and reduces the proinflammatory effects of MPO.

Neutrophil Activation in Response to Toll-Like Receptor Stimulation is Regulated by Platelets

Introduction: Platelets contribute to pathological inflammation during myocardial infarction (MI) and can mediate this response by interacting with neutrophils, which, when activated, can also contribute to myocardial inflammation. Both cells can regulate inflammation by expression of Toll-like receptors (TLRs), but the extent to which platelets modulate neutrophil activation in response to TLR stimulation is currently not understood.

HIV-1-derived single-stranded RNA acts as activator of human neutrophils.

Neutrophils are key effector cells of the innate immune system and are involved in the host defense against invading pathogens such as viruses. Recently, it was reported that HIV-1-neutrophil interaction triggers neutrophil activation and promotes expression of Toll-like receptors (TLRs). Here, we assessed the role of single-stranded RNA40 (ssRNA40) derived from HIV-1 in neutrophil activation. We observed functional activation of neutrophils in response to HIV-1-derived ssRNA40 based on the expression of TLR7/8, RIG-I, and MDA5, induction of cytokines (IL-6 and TNF-α), and the production of reactive oxygen species (ROS). Additionally, ssRNA40 promoted the expression of CD62L and TNF-α and the production of ROS in the presence of the TLR2 agonist Pam2CSK4. ssRNA40 together with R848 (a TLR7/8 agonist) increased CD11b expression but decreased CD62L expression. Furthermore, decreased IL-6 expression was observed in the presence of the TLR4 agonist LPS. Finally, we found that ssRNA40 promotes RIG-I and MDA5 expression in the presence of the TLR2, TLR4 and TLR7/8 agonists. This study demonstrates a functional response of TLRs in neutrophils challenged with ssRNA40, suggesting that TLRs could be involved in the innate immune response observed during HIV infection, which might be mediated by its genome.

Colchicine protects rat skeletal muscle from ischemia/reperfusion injury by suppressing oxidative stress and inflammation.

Neutrophils play an important role in ischemia/reperfusion (IR) induced skeletal muscle injury. Microtubules are required for neutrophil activation in response to various stimuli. This study aimed to investigate the effects of colchicine, a microtubule-disrupting agent, on skeletal muscle IR injury in a rat hindlimb ischemia model. Twenty-one Sprague-Dawley rats were randomly allocated into three groups IR group, colchicine treated-IR (CO) group and sham operation (SM) group. Rats of both the IR and CO groups were subjected to 3 hr of ischemia by clamping the right femoral artery followed by 2 hr of reperfusion. Colchicine (1 mg/kg) was administrated intraperitoneally prior to hindlimb ischemia in the CO group. After 2 hr of reperfusion, we measured superoxide dismutase (SOD) and myeloperoxidase (MPO) activities, and malondialdehyde (MDA), tumor necrosis factor (TNF)-α and interleukin (IL)-1β levels in the muscle samples. Plasma creatinine kinase (CK) and lactate dehydrogenase (LDH) levels were measured. We also evaluated the histological damage score and wet/dry weight (W/D) ratio. The histological damage score, W/D ratio, MPO activity, MDA, TNF-α and IL-1β levels in muscle tissues were significantly increased, SOD activity was decreased, and plasma CK and LDH levels were remarkably elevated in both the IR and CO groups compared to the SM group (P<0.05). Colchicine treatment significantly reduced muscle damage and edema, oxidative stress and levels of the inflammatory parameters in the CO group compared to the IR group (P<0.05). Colchicine attenuates IR-induced skeletal muscle injury in rats.

Identifying the Critical Domain of LL-37 Involved in Mediating Neutrophil Activation in the Presence of Influenza Virus: Functional and Structural Analysis.

The human cathelicidin LL-37 has been shown to play a role in host defense against influenza A viruses (IAV) through direct antiviral effects and through modulating inflammatory responses to infection. We recently showed that LL-37 increases neutrophil respiratory burst and neutrophil extracellular trap (NET) responses to IAV through engaging formyl peptide receptor 2 (FPR-2). In this paper we show that a fragment of LL-37, GI-20, which is composed of the central helical segment of the peptide, has similar effects as LL-37 on neutrophil activation. In addition to increasing respiratory burst and NET responses of the cells to IAV through an FPR-2 dependent mechanism, it reduces neutrophil IL-8 production to IAV (also like LL-37). The N-terminal fragment, LL-23, did not have similar effects. Both GI-20 and LL-37 increase neutrophil intracellular calcium levels and their ability to increase neutrophil activation responses was calcium dependent and partially inhibited by pertussis toxin. These studies show that the central helix of LL-37 retains the ability of LL-37 to modulate neutrophil responses through FPR-2. Based on our findings we developed a homology model of FPR-2 and performed docking experiments of LL-37 and GI-20 with the receptor.

Clec12a: Quieting the Dead

Immune activation as a result of the recognition of damage-associated molecular patterns needs to be controlled. In this issue of Immunity, Neumann etal. (2014) demonstrates that Clec12a is a receptor for dead cells through the recognition of uric acid crystals and contributes to the dampening of the responses.

On-demand, competing gradient arrays for neutrophil chemotaxis.

Neutrophils are the most abundant type of white blood cells in the circulation, protecting the body against pathogens and responding early to inflammation. Although we understand how neutrophils respond to individual stimuli, we know less about how they prioritize between competing signals or respond to combinational signals. This situation is due in part to the lack of adequate experimental systems to provide signals in controlled spatial and temporal fashion. To address these limitations, we designed a platform for generating on-demand, competing chemical gradients and for monitoring neutrophil migration. On this platform, we implemented forty-eight assays generating independent gradients and employed synchronized valves to control the timing of these gradients. We observed faster activation of neutrophils in response to fMLP than to LTB4 and unveiled for the first time a potentiating effect for fMLP during migration towards LTB4. Our observations, enabled by the new tools, challenge the current paradigm of inhibitory competition between distinct chemoattractant gradients and suggest that human neutrophils are capable of complex integration of chemical signals in their environment.

Platelets promote bacterial dissemination in a mouse model of streptococcal sepsis

Platelets have been reported to contribute to inflammation and inflammatory disorders. In the present study, we demonstrate that platelets contribute to the acute response to bacterial infection in a mouse model of invasive Streptococcus pyogenes infection. Thrombocytopenia occurred rapidly in infected animals and this was associated with platelet activation, formation of platelet–neutrophil complexes and neutrophil activation. In order to assess the role of platelets during infection, platelets were depleted prior to infection. Platelet-depleted animals had significantly decreased platelet–neutrophil complex formation and neutrophil activation in response to infection. Importantly, significantly fewer bacteria disseminated to the blood, lungs, and spleen of platelet-depleted animals. Platelet-depleted animals did not decrease as significantly in weight as the infected control animals. The results demonstrate a previously unappreciated role for platelets during the pathophysiological response to infection, whereby S. pyogenes bacteria bind to platelets and platelets facilitate bacterial dissemination.

Nicotinamide Supplementation Protects Gestational Diabetic Rats by Reducing Oxidative Stress and Enhancing Immune Responses

Gestational diabetes (GD) is a common complication during pregnancy. Metabolic changes in GD affect fetal development and fetal glucose homeostasis. The present study utilized a rat model of GD to evaluate the effects of nicotinamide on diabetic parameters; antioxidant gene expression viz, superoxide dismutase (SOD) and catalase (CAT); reactive oxygen species (ROS) production by neutrophils and enhancement of lymphocyte mediated immune response. Nicotinamide (50, 100 and 200 mg/kg) was orally supplemented to gestational diabetic rats from days 6 through 20 of gestation. After GD induction, the control group had elevated glucose and reduced insulin while nicotinamide (100 & 200 mg/kg) supplementation reversed these changes. The same doses of nicotinamide upregulated mRNA expressions of SOD and CAT genes in liver but reduced the oxidative burst activity of neutrophils in response to phorbol myristate acetate (PMA), N-formyl-methionyl-leucyl-phenylalanine (FMLP) or E. coli activation. Nicotinamide (100 & 200 mg/kg) supplementation also increased expression of activated T helper (CD4+CD25+) cells and induced proliferation of splenocytes. These findings provide evidence for utilizing nicotinamide as supplement or adjunct to support existing therapeutic agents for gestational diabetes and in pregnant individuals with weakened immune systems.

Neutrophilic Inflammatory Response and Oxidative Stress in Premenopausal Women Chronically Exposed to Indoor Air Pollution from Biomass Burning

The possibility of inflammation and neutrophil activation in response to indoor air pollution (IAP) from biomass fuel use has been investigated. For this, 142 premenopausal, never-smoking women (median age, 34 years) who cook exclusively with biomass (wood, dung, crop wastes) and 126 age-matched control women who cook with cleaner fuel liquefied petroleum gas (LPG) were enrolled. The neutrophil count in blood and sputum was significantly higher (p < 0.05) in biomass users than the control group. Flow cytometric analysis revealed marked increase in the surface expression of CD35 (complement receptor-1), CD16 (F(C)γ receptor III), and β(2) Mac-1 integrin (CD11b/CD18) on circulating neutrophils of biomass users. Besides, enzyme-linked immunosorbent assay showed that they had 72%, 67%, and 54% higher plasma levels of the proinflammatory cytokines tumor necrosis factor-alpha, interleukin-6, and interleukin-12, respectively, and doubled neutrophil chemoattractant interleukin-8. Immunocytochemical study revealed significantly higher percentage of airway neutrophils expressing inducible nitric oxide synthase, while the serum level of nitric oxide was doubled in women who cooked with biomass. Spectrophotometric analysis documented higher myeloperoxidase activity in circulating neutrophils of biomass users, suggesting neutrophil activation. Flow cytometry showed excess generation of reactive oxygen species (ROS) by leukocytes of biomass-using women, whereas their erythrocytes contained a depleted level of antioxidant enzyme superoxide dismutase (SOD). Indoor air of biomass-using households had two to four times more particulate matter with diameters of <10 μm (PM(10)) and <2.5 μm (PM(2.5)) as measured by real-time laser photometer. After controlling potential confounders, rise in proinflammatory mediators among biomass users were positively associated with PM(10) and PM(2.5) in indoor air, suggesting a close relationship between IAP and neutrophil activation. Besides, the levels of neutrophil activation and inflammation markers were positively associated with generation of ROS and negatively with SOD, indicating a role of oxidative stress in mediating neutrophilic inflammatory response following chronic inhalation of biomass smoke.

Immunomodulatory activity of polyphenols derived from Cassia auriculata flowers in aged rats

The immunomodulatory activity of Cassia auriculata (CA)-derived polyphenols was tested on aged rats. Rats (24–26 months old) were given CA polyphenols supplementation at doses of 25, 50, and 100 mg/kg for 28 days. Flow cytometry analysis of CA polyphenols-treated aged rats showed increased T and B cells percentage along with enhanced proliferation of splenocytes in both resting and LPS-stimulated cells. Increased percentage of pan T cells is further supported by an elevation of CD4+, CD8+, and CD4+CD25+ regulatory cells. In terms of innate immune cell activity, CA polyphenol supplementation reduced the oxidative burst activity of neutrophils in response to PMA and Escherichia coli activation. Our results collectively show that polyphenols derived from CA boost T cell immunity by increasing the number of T cells and its sensitivity towards stimulants and decreasing ROS production by neutrophils that could potentially harm multiple biological systems in aged individuals.