Neutrophil Extracellular Traps Regulate Surgical Brain Injury by Activating the cGAS-STING Pathway.

Surgical brain injury (SBI), induced by neurosurgical procedures or instruments, has not attracted adequate attention. The pathophysiological process of SBI remains sparse compared to that of other central nervous system diseases thus far. Therefore, novel and effective therapies for SBI are urgently needed. In this study, we found that neutrophil extracellular traps (NETs) were present in the circulation and brain tissues of rats after SBI, which promoted neuroinflammation, cerebral edema, neuronal cell death, and aggravated neurological dysfunction. Inhibition of NETs formation by peptidylarginine deiminase (PAD) inhibitor or disruption of NETs with deoxyribonuclease I (DNase I) attenuated SBI-induced damages and improved the recovery of neurological function. We show that SBI triggered the activation of cyclic guanosine monophosphate-adenosine monophosphate synthase stimulator of interferon genes (cGAS-STING), and that inhibition of the cGAS-STING pathway could be beneficial. It is worth noting that DNase I markedly suppressed the activation of cGAS-STING, which was reversed by the cGAS product cyclic guanosine monophosphate-adenosine monophosphate (cGMP-AMP, cGAMP). Furthermore, the neuroprotective effect of DNase I in SBI was also abolished by cGAMP. NETs may participate in the pathophysiological regulation of SBI by acting through the cGAS-STING pathway. We also found that high-dose vitamin C administration could effectively inhibit the formation of NETs post-SBI. Thus, targeting NETs may provide a novel therapeutic strategy for SBI treatment, and high-dose vitamin C intervention may be a promising translational therapy with an excellent safety profile and low cost.

Neutrophil Extracellular Traps in Tumors and Potential Use of Traditional Herbal Medicine Formulations for Its Regulation.

Neutrophil extracellular traps (NETs) are extracellular fibers composed of deoxyribonucleic acid (DNA) and decorated proteins produced by neutrophils. Recently, NETs have been associated with the development of many diseases, including tumors. Herein, we reviewed the correlation between NETs and tumors. In addition, we detailed active compounds from traditional herbal medicine formulations that inhibit NETs, related nanodrug delivery systems, and antibodies that serve as "guiding moieties" to ensure targeted delivery to NETs. Furthermore, we discussed the strategies used by pathogenic microorganisms to evade NETs.

A therapeutic strategy of parthenolide in improving imiquimod-induced psoriasis-like skin inflammation targeting IL-36/NETs through skin transdermal therapeutic system.

BACKGROUND: Psoriasis is an inflammatory skin disease that occurs repeatedly over time. The natural product of sesquiterpene lactones, Parthenolide (Par), is isolated from Tanacetum parthenium L. (feverfew) which has significant effects on anti-inflammatory. The therapeutic effect of the medication itself is crucial, but different routes of administration of the same drug can also produce different effects. PURPOSE: The aim of our research sought to investigate the ameliorating effects of Par in psoriasis-like skin inflammation and its related mechanism of action. RESULTS: In the IMQ-induced model, intragastric administration of Par reduced the Psoriasis Area and Severity Index (PASI) score, improved skin erythema, scaling, and other symptoms. And Par decreased the expression of Ki67, keratin14, keratin16 and keratin17, and increased the expression of keratin1. Par could reduce IL-36 protein expressions, meanwhile the expression of Il1b, Cxcl1 and Cxcl2 mRNA were also decreased. Par regulated the expression levels of F4/80, MPO and NE. However, skin transdermal administration of Par was more effective. Similarly, Par attenuated IL-36γ, IL-1ß and caspase-1 activated by Poly(I:C) in in vitro and ex vivo. In addition, Par also reduced NE, PR3, and Cathepsin G levels in explant skin tissues. CONCLUSION: Par ameliorated psoriasis-like skin inflammation in both in vivo and in vitro, especially after treatment with transdermal drug delivery, possibly by inhibiting neutrophil extracellular traps and thus by interfering IL-36 signaling pathway. It indicated that Par provides a new research strategy for the treatment of psoriasis-like skin inflammation and is expected to be a promising drug.

[Traditional Chinese medicines target neutrophil extracellular traps to treat diseases: a review].

Neutrophil extracellular traps(NETs) are fibrous networks formed by neutrophils after a procedure called NETosis, with the function of capturing and killing pathogens. NETs are widely involved in the pathological processes of major diseases such as immune system diseases, respiratory diseases, metabolic diseases, cancers, and reperfusion injury. Therefore, regulating NETs has become one of the important ways to prevent and treat the above diseases. As an excellent traditional culture in China, traditional Chinese medicine has made outstanding contributions to the treatment of diseases. In recent years, studies have discovered that a variety of active components in traditional Chinese medicines, Chinese medicine compound prescriptions, and single traditional Chinese medicines can alleviate the symptoms by regulating NETs in the pathological process of major diseases. This article reviews the research progress in the regulation of NETs by the active components of traditional Chinese medicines, Chinese medicine compound prescriptions, and single traditional Chinese medicines in the last five years, aiming to serve as a reference for related research.

Augmenting Neutrophil Extracellular Traps with Carbonized Polymer Dots: A Potential Treatment for Bacterial Sepsis.

Sepsis is a life-threatening condition that can progress to septic shock as the body's extreme response to pathogenesis damages its own vital organs. Staphylococcus aureus (S. aureus) accounts for 50% of nosocomial infections, which are clinically treated with antibiotics. However, methicillin-resistant strains (MRSA) have emerged and can withstand harsh antibiotic treatment. To address this problem, curcumin (CCM) is employed to prepare carbonized polymer dots (CPDs) through mild pyrolysis. Contrary to curcumin, the as-formed CCM-CPDs are highly biocompatible and soluble in aqueous solution. Most importantly, the CCM-CPDs induce the release of neutrophil extracellular traps (NETs) from the neutrophils, which entrap and eliminate microbes. In an MRSA-induced septic mouse model, it is observed that CCM-CPDs efficiently suppress bacterial colonization. Moreover, the intrinsic antioxidative, anti-inflammatory, and anticoagulation activities resulting from the preserved functional groups of the precursor molecule on the CCM-CPDs prevent progression to severe sepsis. As a result, infected mice treated with CCM-CPDs show a significant decrease in mortality even through oral administration. Histological staining indicates negligible organ damage in the MRSA-infected mice treated with CCM-CPDs. It is believed that the in vivo studies presented herein demonstrate that multifunctional therapeutic CPDs hold great potential against life-threatening infectious diseases.

Moxibustion-mediated alleviation of synovitis in rats with rheumatoid arthritis through the regulation of NLRP3 inflammasome by modulating neutrophil extracellular traps.

Purpose: This study investigates the potential mechanism of moxibustion in the treatment of rheumatoid arthritis (RA) by regulating the neutrophil extracellular trap (NET)/NOD-like receptor family pyrin domain-containing protein 3 (NLRP3) inflammasome axis with the use of a rat model with adjuvant arthritis (AA). Methods: Four groups, including normal control (NC), AA, moxibustion (MOX), and chlor-amidine (Cl-amidine) were created from 24 Wistar male rats (6 rats/group). After the intervention and treatment respectively, the joint swelling degree (JSD) and arthritis index (AI) were compared. The pathological changes of synovium were observed with hematoxylin and eosin staining and transmission electron microscopy. The formation of NETs in synovial tissues was detected with immunofluorescence staining. The protein expression of myeloperoxidase (MPO), neutrophil elastase (NE), citrullinated histone (Cit-H3), acyl arginine deiminase 4 (PAD-4), and NLRP3 was measured in the synovium of rat ankle joints with western blotting, and the levels of anti-cyclic citrullinated peptide antibody (CCP-Ab) and interleukin (IL)-1ß were examined in rat serum with ELISA. Results: AA modeling markedly increased JSD, AI, synovial protein expression of MPO, NE, Cit-H3, PAD-4, and NLRP3, and serum levels of CCP-Ab and IL-1ß in rats (P < 0.01). JSD and AI, as well as the levels of MPO, NE, Cit-H3, PAD-4, NLRP3, CCP-Ab, and IL-1ß, were significantly lowered in AA rats by MOX and Cl-amidine (P < 0.01). In addition, AA modeling caused severe pathological injury in the synovium of rats, which was annulled by MOX and Cl-amidine. The formation of NETs in synovium was substantially promoted in rats by AA modeling and was significantly reduced in AA rats after the treatment. Conclusion: Moxibustion can markedly alleviate synovitis and repress inflammatory factor release in AA rats, which may be achieved by diminished synthesis of NETs or their constituents and the blocked formation of NLRP3 inflammasome.

Mercury-containing preparations attenuate neutrophil extracellular trap formation in mice and humans through inhibiting the ERK1/2 pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Neutrophil extracellular trap (NET) formation plays a crucial role in wound healing disorders, including chronic skin ulcers and diabetic foot ulcers (DFUs). Over the years, traditional Chinese topical medications, such as Cinnabar (composed of HgS and soluble mercury salt) and hydrargyria oxydum rubrum (containing HgO and soluble mercury salt), have been utilized for treating these ailments. Nevertheless, the fundamental processes remain mostly ambiguous. AIM OF THE STUDY: This study sought to investigate the potential effects of topical mercury-containing preparations on the process of NET formation. MATERIALS AND METHODS: Neutrophils isolated from healthy individuals and mouse models of type 1 and type 2 diabetes were cultured with phorbol 12-myristate 13-acetate (PMA), both with and without the mercury-containing preparations (MCP). The formation of NETs was monitored using confocal and scanning electron microscopes. Immunofluorescence and fluorescent probes were employed to assess the levels of citrulline histone H3 (Cit-H3) and intracellular reactive oxygen species (ROS), respectively. The impact of MCP extracts on cytokine expression, peptidylarginine deiminase 4 (PAD4), and myeloperoxidase (MPO) was measured through Luminex and ELISA assays. Phagocytosis of human neutrophils was analyzed using Flow Cytometry. Finally, the phosphorylation levels of ERK were detected by western blotting. RESULTS: Treatment with MCP led to a reduction in PAD4, Cit-H3, and MPO expressions in neutrophils, consequently inhibiting PMA-induced NET formation. MCP treatment also dampened ERK1/2 activation in neutrophils. Furthermore, MCP exhibited inhibitory effects on the secretion of the cytokine IL-8 and ROS production while enhancing neutrophil phagocytosis. CONCLUSION: Our findings suggest that MCP can mitigate the release of NETs, likely by suppressing the ERK1/2 signaling pathway.

Role and Therapeutic Targeting Strategies of Neutrophil Extracellular Traps in Inflammation.

Neutrophil extracellular traps (NETs) are large DNA reticular structures secreted by neutrophils and decorated with histones and antimicrobial proteins. As a key mechanism for neutrophils to resist microbial invasion, NETs play an important role in the killing of microorganisms (bacteria, fungi, and viruses). Although NETs are mostly known for mediating microbial killing, increasing evidence suggests that excessive NETs induced by stimulation of physical and chemical components, microorganisms, and pathological factors can exacerbate inflammation and organ damage. This review summarizes the induction and role of NETs in inflammation and focuses on the strategies of inhibiting NETosis and the mechanisms involved in pathogen evasion of NETs. Furthermore, herbal medicine inhibitors and nanodelivery strategies improve the efficiency of inhibition of excessive levels of NETs.

Effect of Antioxidant Supplementation on NET Formation Induced by LPS In Vitro; the Roles of Vitamins E and C, Glutathione, and N-acetyl Cysteine.

Neutrophil extracellular traps (NETs) require reactive oxygen species (ROS) to eliminate pathogens by inducing oxidative stress. However, this process can also cause tissue damage to the host. Neutrophils contain high concentrations of vitamin C (1.5 mM) compared to the bloodstream (0.1 mM), and this antioxidant can interact with vitamin E and glutathione (GSH) inside the cell to maintain the redox balance. Previous studies have investigated the effect of vitamins E or C and N-acetyl cysteine (NAC) on NET formation, but the interactions of these molecules in neutrophils remain unknown. In this study, we investigated the effect of antioxidants alone and two combinations on NET formation and oxidative stress. Neutrophils were pre-loaded with GSH + NAC or vitamin E + vitamin C + GSH + NAC (termed ALL), and LPS-induced NET formation was assessed using fluorometry and immunofluorescence. Antioxidant effects were evaluated by measuring the total antioxidant capacity (TAC), GSH/GSSG ratio, ROS production, nitrite + nitrate levels, and lipid peroxidation. Our results showed that even low doses of antioxidants are capable of decreasing NETs. Furthermore, the combinations augmented TAC and GSH/GSSG ratio and decreased ROS, nitrites + nitrates, and malondialdehyde (MDA) levels in supplemented neutrophils in vitro.

Rosavin inhibits neutrophil extracellular traps formation to ameliorate sepsis-induced lung injury by regulating the MAPK pathway.

BACKGROUND: Sepsis is a systemic organ dysfunction caused by infection, and the most affected organ is the lungs. Rosavin, a traditional Tibetan medicine, exerts an impressive anti--inflammatory effect. However, its effects on sepsis-related lung damage have not been investigated. PURPOSE: This study aimed to investigate the effects of Rosavin on cecal ligation and puncture (CLP)-induced lung injury. METHODS: The sepsis mouse model was established by CLP, and the mice were pretreated with Rosavin to explore whether it contributed to the alleviation of lung injury. Hematoxylin-eosin (H&E) stain and lung injury score were used to assess the severity of lung injury. The bronchoalveolar lavage fluid (BALF) inflammatory mediators (tumor necrosis factor-α [TNF-α], interleukin-6 [IL-6], IL-1ß, and IL-17A) were detected by ELISA. The number of neutrophils in BALF was detected using flow cytometry. The immunofluorescence assay was used to detect histone and myeloperoxidase (MPO) in lung tissues. Then, the western blot was performed to detect the expression of mitogen-activated protein kinase (MAPK) pathways (extracellular regulated kinase [ERK], p-ERK, p38, p-p38, Jun N-terminal kinase 1/2 [JNK1/2], and p-JNK1/2) in lung tissues. RESULTS: We found that Rosavin significantly attenuated sepsis-induced lung injury. Specifically, Rosavin significantly inhibited inflammation response by decreasing the secretion of inflammatory mediators. The level of neutrophil extracellular traps (NETs) and MPO activity in CLP were decreased after administration with Rosavin. Moreover, the western blot showed that Rosavin could suppress NETs formation by inhibiting the MAPK/ERK/p38/JNK signaling pathway. CONCLUSION: These findings demonstrated that Rosavin inhibited NETs formation to attenuate sepsis-induced lung injury, and the inhibitory effect may be exerted via deregulation of the MAPK pathways.

Selenium-rich yeast counteracts the inhibitory effect of nanoaluminum on the formation of porcine neutrophil extracellular traps.

Aluminum is widely used in daily life due to its excellent properties. However, aluminum exposure to the environment severely threatens animal and human health. Conversely, selenium (Se) contributes to maintaining the balance of the immune system. Neutrophils exert immune actions in several ways, including neutrophil extracellular traps (NETs) that localize and capture exogenous substances. Despite the recent investigations on the toxic effects of aluminum and its molecular mechanisms, the immunotoxicity of aluminum nanoparticles on pigs and the antagonistic effect of selenium on aluminum toxicity are poorly understood. Here, we treated porcine peripheral blood neutrophils with zymosan for 3 h to induce NETs formation. Then, we investigated the effect of nanoaluminum on NETs formation in pigs and its possible molecular mechanisms. Microscopy observations revealed that NETs formation was inhibited by nanoaluminum. Using a multifunctional microplate reader, the production of extracellular DNA and the burst of reactive oxygen species (ROS) in porcine neutrophils were inhibited by nanoaluminum. Western blot analyses showed that nanoaluminum caused changes in amounts of cellular selenoproteins. After Se supplementation, the production of porcine NETs, the burst of ROS, and selenoprotein levels were restored. This study indicated that nanoaluminum inhibited the zymosan-induced burst of ROS and release of NETs from porcine neutrophils, possibly through the selenoprotein signaling pathway. In contrast, Se supplementation reduced the toxic effects of nanoaluminum and restored NETs formation.

Pancreatic melatonin enhances anti-tumor immunity in pancreatic adenocarcinoma through regulating tumor-associated neutrophils infiltration and NETosis.

Tumor microenvironment contributes to poor prognosis of pancreatic adenocarcinoma (PAAD) patients. Proper regulation could improve survival. Melatonin is an endogenous hormone that delivers multiple bioactivities. Here we showed that pancreatic melatonin level is associated with patients' survival. In PAAD mice models, melatonin supplementation suppressed tumor growth, while blockade of melatonin pathway exacerbated tumor progression. This anti-tumor effect was independent of cytotoxicity but associated with tumor-associated neutrophils (TANs), and TANs depletion reversed effects of melatonin. Melatonin induced TANs infiltration and activation, therefore induced cell apoptosis of PAAD cells. Cytokine arrays revealed that melatonin had minimal impact on neutrophils but induced secretion of Cxcl2 from tumor cells. Knockdown of Cxcl2 in tumor cells abolished neutrophil migration and activation. Melatonin-induced neutrophils presented an N1-like anti-tumor phenotype, with increased neutrophil extracellular traps (NETs) causing tumor cell apoptosis through cell-to-cell contact. Proteomics analysis revealed that this reactive oxygen species (ROS)-mediated inhibition was fueled by fatty acid oxidation (FAO) in neutrophils, while FAO inhibitor abolished the anti-tumor effect. Analysis of PAAD patient specimens revealed that CXCL2 expression was associated with neutrophil infiltration. CXCL2, or TANs, combined with NET marker, can better predict patients' prognosis. Collectively, we discovered an anti-tumor mechanism of melatonin through recruiting N1-neutrophils and beneficial NET formation.

Platelet activation and ferroptosis mediated NETosis drives heme induced pulmonary thrombosis.

Cell-free heme (CFH) is a product of hemoglobin, myoglobin and hemoprotein degradation, which is a hallmark of pathologies associated with extensive hemolysis and tissue damage. CHF and iron collectively induce cytokine storm, lung injury, respiratory distress and infection susceptibility in the lungs suggesting their key role in the progression of lung disease pathology. We have previously demonstrated that heme-mediated reactive oxygen species (ROS) induces platelet activation and ferroptosis. However, interaction of ferroptotic platelets and neutrophils, the mechanism of action and associated complications remain unclear. In this study, we demonstrate that heme-induced P-selectin expression and Phosphatidylserine (PS) externalization in platelets via ASK-1-inflammasome axis increases platelet-neutrophil aggregates in circulation, resulting in Neutrophil extracellular traps (NET) formation in vitro and in vivo. Further, heme-induced platelet activation in mice increased platelet-neutrophil aggregates and accumulation of NETs in the lungs causing pulmonary damage. Thus, connecting CFH-mediated platelet activation to NETosis and pulmonary thrombosis. As lung infections induce acute respiratory stress, thrombosis and NETosis, we propose that heme -mediated platelet activation and ferroptosis might be crucial in such clinical manifestations. Further, considering the ability of redox modulators and ferroptosis inhibitors like FS-1, Lpx-1 and DFO to inhibit heme-induced ferroptotic platelets-mediated NETosis and pulmonary thrombosis. They could be potential adjuvant therapy to regulate respiratory distress-associated clinical complications.

Anti-inflammatory and antiviral activities of flavone C-glycosides of Lophatherum gracile for COVID-19.

Lophatherum gracile (L. gracile) has long been used as a functional food and herbal medicine. Previous studies have demonstrated that extracts of L. gracile attenuate inflammatory response and inhibit SARS-CoV-2 replication; however, the underlying active constituents have yet to be identified. This study investigated the bioactive components of L. gracile. Flavone C-glycosides of L. gracile were found to dominate both anti-inflammatory and antiviral effects. A simple chromatography-based method was developed to obtain flavone C-glycoside-enriched extract (FlavoLG) from L. gracile. FlavoLG and its major flavone C-glycoside isoorientin were shown to restrict respiratory bursts and the formation of neutrophil extracellular traps in activated human neutrophils. FlavoLG and isoorientin were also shown to inhibit SARS-CoV-2 pseudovirus infection by interfering with the binding of the SARS-CoV-2 spike on ACE2. These results provide scientific evidence indicating the efficacy of L. gracile as a potential supplement for treating neutrophil-associated COVID-19.

Epigallocatechin-3-gallate inhibits the formation of neutrophil extracellular traps and suppresses the migration and invasion of colon cancer cells by regulating STAT3/CXCL8 pathway.

Colon cancer is a common malignant tumor of the digestive tract. Tea catechin exerts anti-tumor effects in colon cancer. This work aimed to determine the functions of epigallocatechin-3-gallate (EGCG), one of the main active components of Tea catechins, in the progression of colon cancer. In this work, enzyme-linked immune-sorbent assay, quantitative real-time PCR and western blotting was utilized to examine the levels of IL-1ß, TNF-α, STAT3, p-STAT3 and CXCL8 in colon cancer patients and healthy controls. Compared with healthy controls, the levels of IL-1ß and TNF-α were significantly increased in the peripheral blood of colon cancer patients, and the expression of STAT3, p-STAT3 and CXCL8 was elevated in the neutrophils derived from colon cancer patients. Moreover, neutrophils were treated with phorbol ester (PMA) or DNase I to induce or impede the formation of neutrophil extracellular traps (NETs). Both STAT3 overexpression and PMA treatment promoted the expression of CXCL8, myeloperoxidase (MPO) and citrullinated histone H3 (H3Cit) in the colon cancer-derived neutrophils, indicating that STAT3 overexpression facilitated the formation of NETs. STAT3 deficiency suppressed the formation of NETs, which consistent with the results of DNase I treatment. Transwell assay was utilized to detect the migration and invasion of colon cancer cell line SW480. EGCG treatment suppressed the formation of NETs and the expression of STAT3 and CXCL8 in the colon cancer-derived neutrophils, and then inhibited the migration and invasion of SW480 cells. In conclusion, this work demonstrated that EGCG inhibited the formation of NETs and subsequent suppressed the migration and invasion of colon cancer cells by regulating STAT3/CXCL8 signalling pathway. Thus, this study suggests that EGCG may become a potential drug for colon cancer therapy.

Hydroxycarboxylic acid receptor 2 (HCA2) agonists induce NET formation and MMP-9 release from bovine polymorphonuclear leukocytes.

Periparturient cows are commonly fed diets supplemented with Niacin (nicotinic acid, NA) because of its anti-lipolytic properties. NA confers its anti-lipolytic effects by activating the hydroxycarboxylic acid 2 receptor (HCA2). HCA2 is also activated by the ketone body beta-hydroxybutyrate (BHB) and circulating BHB levels are elevated in postpartum dairy cows. The HCA2 receptor is highly expressed in bovine polymorphonuclear leukocytes (PMN) and could link metabolic and innate immune responses in cattle. We investigated how HCA2 agonists affected bovine PMN function in vitro. We studied different PMN responses, such as granule release, surface expression of CD11b and CD47, generation of neutrophil extracellular traps (NETs), and apoptosis. NA, BHB, and 4,4aR,5,5aR-tetrahydro-1H-cyclopropa [4,5] cyclopenta [1,2-c] pyrazole-3-carboxylic acid (MK-1903) treatment triggered the release of matrix metalloproteinase 9 (MMP-9), a component of the tertiary granule, from neutrophils. Additionally, all HCA2 agonists induced NETs formation but did not affect surface expression of CD11b and CD47. Finally, none of the HCA2 agonists triggered apoptosis in bovine PMN. This information will give new insights into the potential role of the HCA2 receptor in the bovine innate immune response.

Pancreatic melatonin enhances anti-tumor immunity in pancreatic adenocarcinoma through regulating tumor-associated neutrophils infiltration and NETosis

Tumor microenvironment contributes to poor prognosis of pancreatic adenocarcinoma (PAAD) patients. Proper regulation could improve survival. Melatonin is an endogenous hormone that delivers multiple bioactivities. Here we showed that pancreatic melatonin level is associated with patients' survival. In PAAD mice models, melatonin supplementation suppressed tumor growth, while blockade of melatonin pathway exacerbated tumor progression. This anti-tumor effect was independent of cytotoxicity but associated with tumor-associated neutrophils (TANs), and TANs depletion reversed effects of melatonin. Melatonin induced TANs infiltration and activation, therefore induced cell apoptosis of PAAD cells. Cytokine arrays revealed that melatonin had minimal impact on neutrophils but induced secretion of Cxcl2 from tumor cells. Knockdown of Cxcl2 in tumor cells abolished neutrophil migration and activation. Melatonin-induced neutrophils presented an N1-like anti-tumor phenotype, with increased neutrophil extracellular traps (NETs) causing tumor cell apoptosis through cell-to-cell contact. Proteomics analysis revealed that this reactive oxygen species (ROS)-mediated inhibition was fueled by fatty acid oxidation (FAO) in neutrophils, while FAO inhibitor abolished the anti-tumor effect. Analysis of PAAD patient specimens revealed that CXCL2 expression was associated with neutrophil infiltration. CXCL2, or TANs, combined with NET marker, can better predict patients' prognosis. Collectively, we discovered an anti-tumor mechanism of melatonin through recruiting N1-neutrophils and beneficial NET formation.

The Effect of Vitamin D3 on Neutrophil Extracellular Trap Formation in High-Glucose Conditions.

NETosis, i.e., the formation of neutrophil extracellular traps (NET), and neutrophil autophagy are important elements in the pathogenesis and the development of complications of type 2 diabetes mellitus (T2DM). Therefore, the search of drugs that can regulate the level of NETosis and autophagy in T2DM is relevant. Here we studied an ex vivo NET formation and neutrophil death in whole blood from healthy subjects upon the addition of glucose up to a high concentration of 15 mM or/and the phorbol ester PMA (phorbol-12-myristate-13-acetate). Their individual and combined action caused neutrophil death and an increase in NET content. It can be hypothesized that this resulted from activation of NETosis and autophagy. It was also shown that this activation of NETosis and autophagy is completely prevented by daily intake of 1000 IU vitamin D3 for 14 days. Therefore, vitamin D3 supplementation can be considered as a preventive measure against the development of T2DM complications.

Febrile-Range Hyperthermia Can Prevent Toxic Effects of Neutrophil Extracellular Traps on Mesenchymal Stem Cells.

Fracture healing is characterized by an inflammatory phase directly after fracture which has a strong impact on the healing outcome. Neutrophils are strong contributors here and can release neutrophil extracellular traps (NETs). NETs are found after trauma, originally thought to capture pathogens. However, they can lead to tissue damage and impede wound healing processes. Their role in fracture healing remains unclear. In this study, the effect of isolated NETs on the function of bone-forming mesenchymal stem cells (SCP-1 cells) was examined. NETs were isolated from stimulated healthy neutrophils and viability, migration, and differentiation of SCP-1 cells were analyzed after the addition of NETs. NETs severely impaired the viability of SCP-1 cells, induced necrosis and already nontoxic concentrations reduced migration significantly. Short-term incubation with NETs had a persistent negative effect on osteogenic differentiation, as measured by AP activity and matrix formation. The addition of DNase or protease inhibitors failed to reverse the negative effect of NETs, whereas a short febrile-range temperature treatment successfully reduced the toxicity and membrane destruction. Thus, the possible modification of the negative effects of NETs in fracture hematomas could be an interesting new target to improve bone healing, particularly in patients with chronic diseases such as diabetes.

Preventive Effect of Epigallocatechin Gallate, the Main Component of Green Tea, on Acute Lung Injury Caused by Air Pollutants.

Reducing the health hazards caused by air pollution is a global challenge and is included in the Sustainable Development Goals. Air pollutants, such as PM2.5, induce respiratory and cardiovascular disorders by causing various inflammatory responses via oxidative stress. Catechins and polyphenols, which are components of green tea, have various protective effects, owing to their antioxidant ability. The main catechin in green tea, epigallocatechin gallate (EGCG), is potentially effective against respiratory diseases, such as idiopathic pulmonary fibrosis and asthma, but its effectiveness against air-pollution-dependent lung injury has not yet been investigated. In this study, we examined the effect of EGCG on urban aerosol-induced acute lung injury in mice. Urban aerosol treatment caused increases in inflammatory cell counts, protein levels, and inflammatory cytokine expression in the lungs of ICR mice, but pretreatment with EGCG markedly suppressed these responses. Analyses of oxidative stress revealed that urban aerosol exposure enhanced reactive oxygen species (ROS) production and the formation of ROS-activated neutrophil extracellular traps (NETs) in the lungs of mice. However, ROS production and NETs formation were markedly suppressed by pretreating the mice with EGCG. Gallocatechin gallate (GCG), a heat-epimerized form of EGCG, also markedly suppressed urban aerosol-dependent inflammatory responses and ROS production in vivo and in vitro. These findings suggest that EGCG and GCG prevent acute lung injury caused by urban aerosols through their inhibitory effects on ROS production. Thus, we believe that foods and medications containing EGCG or GCG may be candidates to prevent the onset and progression of acute lung injury caused by air pollutants.