Neutrophil Migration Research Articles

Decade of insights: Bleomycin-induced pneumonitis and use of G-CSF in chemotherapy-treated germ cell testicular tumors and Hodgkin lymphoma—Real-world outcomes from an academic cancer center.

e17013 Background: Bleomycin induced pulmonary toxicity (BIP) occurs in 4-10% of treated patients. Preclinical reports suggest G-CSF use may increase BIP risk, due to neutrophil migration to lung tissues. Limited real-world clinical data is available and G-CSF use may reduce risk of treatment related toxicity with curative bleomycin combination treatment. Methods: We conducted a retrospective study of patients with GCT (Germ cell tumor) and HL (Hodgkin’s lymphoma) receiving bleomycin containing chemotherapy and at-least on dose of G-CSF at The James Cancer Center from 2010-2022 using the institutional database. BIP was diagnosed mainly using clinical symptoms complemented by radiological evidence when possible. We reviewed 361 patients, 145 in GCT group and 216 in HL group and clinically relevant information was recorded.Descriptive statistics for the study variables were presented using frequencies and percentages overall. The bivariate associations between G-CSF use and clinical outcomes were assessed using chi-square tests or fisher’s exact tests for the overall sample, and by chemotherapy type. We used SPSS 26.0 for all the statistical analyses, and an alpha level of 0.05 (two-sided) was used for all the tests. Results: Data on 361 patients, including 145 GCT and 216 HL patients treated with at least one dose of bleomycin was available. The median age was 36.3 years in the GCT group and 44.2 years in the HL group.144 patients in the GCT and 50 patients in the HL group received at least 1 dose of G-CSF. BIP occurred in 4.8% in the GCT and 7.4% of patients in the HL group. Only 2 out of 16 patients developing BIP in the HL group received G-CSF. All patients with BIP developed symptomatic disease. On bivariate analysis, no association was noted between BIP and G-CSF in either group (p-value =1.00 in GCT and p-value = 0.32 in HL). Febrile neutropenia (FN) was reported in 4 patients in the GCT group and 29 in the HL group. In the HL subgroup, 28 (28/29) patients developing FN did not receive G-CSF (p-value=0.0008). All patients who developed FN required hospital admission. Conclusions: Use of G-CSF in patients receiving bleomycin was not associated with an increased incidence of BIP. Incidence of FN was higher in patients not receiving G-CSF leading to hospital admissions. [Table: see text]

Anti-apoptotic and anti-inflammatory protective mechanisms of Gmelina arborea stem bark extract on ischemic reperfusion injury in albino Wistar rats

Abstract Ethnopharmacological relevance Gemlina arborea Roxb. ex.’s entire plant is utilized in medicine to treat several diseases. Objective and design Cerebral infarction occurs through multiple mechanisms, and herbs are natural multi-component with numerous protective mechanisms. This research investigates the neuroprotective effect of Gemlina arborea stem bark extract in preventing cerebral infarction. Methodology Male albino Wistar rats were inducted with ischemic injury using the bilateral common carotid artery occlusion method. Neurological effects were examined by motor defects, locomotor activity, and forced swim test, while biochemical activities of the brain oxidative stress biomarkers studied include; (lipid peroxidation, superoxide dismutase, catalase levels, glutathione levels, total calcium levels, and sodium-potassium-ATPase) and histopathological examination. Western blotting analysis was used to study the anti-apoptotic and anti-inflammatory mechanisms. Results The elevated oxidative stress biomarkers in the treated group showed extract-inhibited cerebral infarction. Histological examination shows inhibited neutrophil migration and cell damage. The western blot assay depicts reductions in the inflammatory indicators (p38 MAPK, TNF- α) and attenuation of apoptotic mediators (Bcl2/Bax ratio), down-regulation of caspase-3 expression, and a significantly raised anti-inflammatory mediators (IL-10 and actin) in a dose-dependent manner, suggested potential mechanisms by which the extract prevented ischemic reperfusion injury. Conclusion Overall, the estimation of inflammatory and apoptotic mediators revealed the involvement of the anti-inflammatory mechanisms of Gmelina arborea stem bark extract in preventing cerebral infarction.

Targeting Gαi2 in neutrophils protects from myocardial ischemia reperfusion injury.

Neutrophils are not only involved in immune defense against infection but also contribute to the exacerbation of tissue damage after ischemia and reperfusion. We have previously shown that genetic ablation of regulatory Gαi proteins in mice has both protective and deleterious effects on myocardial ischemia reperfusion injury (mIRI), depending on which isoform is deleted. To deepen and analyze these findings in more detail the contribution of Gαi2 proteins in resident cardiac vs circulating blood cells for mIRI was first studied in bone marrow chimeras. In fact, the absence of Gαi2 in all blood cells reduced the extent of mIRI (22,9% infarct size of area at risk (AAR) Gnai2-/- → wt vs 44.0% wt → wt; p < 0.001) whereas the absence of Gαi2 in non-hematopoietic cells increased the infarct damage (66.5% wt → Gnai2-/- vs 44.0% wt → wt; p < 0.001). Previously we have reported the impact of platelet Gαi2 for mIRI. Here, we show that infarct size was substantially reduced when Gαi2 signaling was either genetically ablated in neutrophils/macrophages using LysM-driven Cre recombinase (AAR: 17.9% Gnai2fl/fl LysM-Cre+/tg vs 42.0% Gnai2fl/fl; p < 0.01) or selectively blocked with specific antibodies directed against Gαi2 (AAR: 19.0% (anti-Gαi2) vs 49.0% (IgG); p < 0.001). In addition, the number of platelet-neutrophil complexes (PNCs) in the infarcted area were reduced in both, genetically modified (PNCs: 18 (Gnai2fl/fl; LysM-Cre+/tg) vs 31 (Gnai2fl/fl); p < 0.001) and in anti-Gαi2 antibody-treated (PNCs: 9 (anti-Gαi2) vs 33 (IgG); p < 0.001) mice. Of note, significant infarct-limiting effects were achieved with a single anti-Gαi2 antibody challenge immediately prior to vessel reperfusion without affecting bleeding time, heart rate or cellular distribution of neutrophils. Finally, anti-Gαi2 antibody treatment also inhibited transendothelial migration of human neutrophils (25,885 (IgG) vs 13,225 (anti-Gαi2) neutrophils; p < 0.001), collectively suggesting that a therapeutic concept of functional Gαi2 inhibition during thrombolysis and reperfusion in patients with myocardial infarction should be further considered.

The Glabridin from Huangqin Decoction Prevents the Development of Ulcerative Colitis into Colitis-Associated Colorectal Cancer by Modulating MMP1/MMP3 Activity

Background and AimHuangqin decoction (HQD) is a Chinese medicine used to treat colitis and colorectal cancer (CRC). However, the specific compounds and mechanisms of HQD remain unclear despite its good curative clinical results. Through bioinformatics, network pharmacology, and experiments, this study aims to explore the progressive mechanisms of colitis-associated colorectal cancer (CAC) from ulcerative colitis (UC) while examining the protective effects of HQD and its compounds against this. MethodsBioinformatics was utilized to identify the hub genes between UC and CRC, and their clinical predictive significance, function, and expression were validated. Employing network pharmacology in combination with hub genes, key targets of HQD for preventing the development of UC into CAC were identified. Molecular docking and molecular dynamics (MD) were utilized to procure compounds that effectively bind to these targets and their transcription factors (TFs). Finally, the expression and mechanism of key targets were demonstrated in mice with UC or CAC. Results(1) Joint analysis of UC and CRC gene sets resulted in 14 hub genes, mainly related to extracellular matrix receptor binding, biological processes in the extracellular matrix, focal adhesion and neutrophil migration; (2) Network pharmacology results show HQD has 133 core targets for treating UC and CRC, acting on extracellular matrix, inflammatory bowel disease, chemical carcinogen receptor activation and other pathways; (3) The intersection of hub genes and core targets yielded two key targets, MMP1 and MMP3; (4) STAT3 is a shared TF of MMP1 and MMP3. (5) Molecular docking and MD verified that the dockings between Glabridin and STAT3/MMP1/MMP3 are stable and reliable; (6) In murine vivo experiments verified that Glabridin reduces inflammation, extracellular matrix degradation, and the occurrence of epithelial-mesenchymal transition to prevent UC transforming into CAC by inhibiting the phosphorylation of STAT3 and regulating the activity of MMP1/3.

Inflammatory bowel diseases and modern methods of their treatment

Chronic inflammatory bowel diseases are a group of diseases that still do not have a specific cause of their occurrence, are characterized by a particularly complex pathogenesis, a variety of clinical manifestations and a significant impact on the patient’s quality of life. Crohn’s disease and non-specific ulcerative colitis are diseases that run with the risk of severe exacerbations and can also lead to the patient’s disability. The main task in the treatment of inflammatory bowel diseases is the initiation of the remission stage and its long-term maintenance. For this, several groups of drugs are used, among which the drug of the first line of therapy is Mesalazine (Mesacol®), its effect on the intestinal wall consists in preventing the development of the inflammatory process by reducing the synthesis of pro-inflammatory prostaglandins and leukotrienes, slowing down the migration, degranulation and phagocytosis of neutrophils. In addition, mesalazine neutralizes free radicals, which increases the protective effect on the intestinal wall.

Astilbin inhibited neutrophil extracellular traps in gouty arthritis through suppression of purinergic P2Y6 receptor

BackgroundGouty arthritis (GA), a common inflammatory condition triggered by monosodium urate crystal accumulation, often necessitates safer treatment alternatives due to the limitations of current therapies. Astilbin, a flavonoid from Smilax glabra Roxb, has demonstrated potential in traditional Chinese medicine for its anti-inflammatory properties. However, the anti-GA effect and its underlying mechanism have not been fully elucidated. PurposeThis study aimed to investigate the therapeutic potential of astilbin in GA, focusing on its effects on neutrophil extracellular traps (NETs), as well as the potential molecular target of GA both in vitro and in vivo. Study designFirstly, astilbin inhibited the citrullinated histone H3 (Cit h3) protein levels and reduced the NETs formation in neutrophils stimulated by monosodium urate (MSU). Secondly, we wondered the effect of astilbin on migration of neutrophils and dimethyl-sulfoxide (DMSO)-differentiated HL-60 (dHL-60) cells under the stimulation of MSU. Then, the effect of astilbin on suppressing NETs through purinergic P2Y6 receptor (P2Y6R) and Interlukin-8 (IL-8)/ CXC chemokine receptor 2 (CXCR2) pathway was investigated. Also, the relationship between P2Y6R and IL-8/CXCR2 was explored in dHL-60 cells under stimulation of MSU. Finally, we testified the effect of astilbin on reducing NETs in GA through suppressing P2Y6R and then down-regulating IL-8/CXCR2 pathway. MethodsMSU was used to induce NETs in neutrophils and dHL-60 cells. Real-time formation of NETs and migration of neutrophils were monitored by cell living imaging with or without MSU. Then, the effect of astilbin on NETs formation, P2Y6R and IL-8/CXCR2 pathway were detected by immunofluorescence (IF) and western blotting. P2Y6R knockdown dHL-60 cells were established by small interfering RNA to investigate the association between P2Y6R and IL-8/CXCR2 pathway. Also, plasmid of P2Y6R was used to overexpress P2Y6R in dHL-60 cells, which was employed to explore the role of P2Y6R in astilbin inhibiting NETs. Within the conditions of knockdown and overexpression of P2Y6R, migration and NETs formation were assessed by transmigration assay and IF staining, respectively. In vivo, MSU-induced GA mice model was established to assess the effect of astilbin on inflammation by haematoxylin-eosin and ELISA. Additionally, the effects of astilbin on neutrophils infiltration, NETs, P2Y6R and IL-8/CXCR2 pathway were analyzed by IF, ELISA, immunohistochemistry (IHC) and western blotting. ResultsUnder MSU stimulation, astilbin significantly suppressed the level of Cit h3 and NETs formation including the fluorescent expressions of Cit h3, neutrophils elastase, myeloperoxidase, and intra/extracellular DNA. Also, results showed that MSU caused NETs release in neutrophils as well as a trend towards recruitment of dHL-60 cells to MSU. Astilbin could markedly decrease expressions of P2Y6R and IL-8/CXCR2 pathway which were upregulated by MSU. By silencing P2Y6R, the expression of IL-8/CXCR2 pathway and migration of dHL-60 cells were inhibited, leading to the suppression of NETs. These findings indicated the upstream role of P2Y6R in the IL-8/CXCR2 pathway. Moreover, overexpression of P2Y6R was evidently inhibited by astilbin, causing a downregulation in IL-8/CXCR2 pathway, migration of dHL-60 cells and NETs formation. These results emphasized that astilbin inhibited the IL-8/CXCR2 pathway primarily through P2Y6R. In vivo, astilbin administration led to marked reductions in ankle swelling, inflammatory infiltration as well as neutrophils infiltration. Expressions of P2Y6R and IL-8/CXCR2 pathway were evidently decreased by astilbin and P2Y6R inhibitor MRS2578 either alone or in combination. Also, astilbin and MRS2578 showed notable effect on reducing MSU-induced NETs formation and IL-8/CXCR2 pathway whether used alone or in combination, parallelly demonstrating that astilbin decreased NETs formation mainly through P2Y6R. ConclusionThis study revealed that astilbin suppressed NETs formation via downregulating P2Y6R and subsequently the IL-8/CXCR2 pathway, which evidently mitigated GA induced by MSU. It also highlighted the potential of astilbin as a promising natural therapeutic for GA.

Paracrinal regulation of neutrophil functions by coronaviral infection in iPSC-derived alveolar type II epithelial cells

Coronaviruses (CoVs) are enveloped single-stranded RNA viruses that predominantly attack the human respiratory system. In recent decades, several deadly human CoVs, including SARS-CoV, SARS-CoV-2, and MERS-CoV, have brought great impact on public health and economics. However, their high infectivity and the demand for high biosafety level facilities restrict the pathogenesis research of CoV infection. Exacerbated inflammatory cell infiltration is associated with poor prognosis in CoV-associated diseases. In this study, we used human CoV 229E (HCoV-229E), a CoV associated with relatively fewer biohazards, to investigate the pathogenesis of CoV infection and the regulation of neutrophil functions by CoV-infected lung cells. Induced pluripotent stem cell (iPSC)-derived alveolar epithelial type II cells (iAECIIs) exhibiting specific biomarkers and phenotypes were employed as an experimental model for CoV infection. After infection, the detection of dsRNA, S, and N proteins validated the infection of iAECIIs with HCoV-229E. The culture medium conditioned by the infected iAECIIs promoted the migration of neutrophils as well as their adhesion to the infected iAECIIs. Cytokine array revealed the elevated secretion of cytokines associated with chemotaxis and adhesion into the conditioned media from the infected iAECIIs. The importance of IL-8 secretion and ICAM-1 expression for neutrophil migration and adhesion, respectively, was demonstrated by using neutralizing antibodies. Moreover, next-generation sequencing analysis of the transcriptome revealed the upregulation of genes associated with cytokine signaling. To summarize, we established an in vitro model of CoV infection that can be applied for the study of the immune system perturbations during severe coronaviral disease.

Cell migration dynamics explained by the coupling of mechanics with electrochemistry and pH regulation

Anisotropic environmental signals or polarized membrane ion/solute carriers can generate spatially varying intracellular gradients, leading to polarized cell dynamics. For example, the directional migration of neutrophils, galvanotaxis of glioblastoma, and water flux in kidney cells all result from the polarized distribution of membrane ion carriers and other intracellular components. The underlying physical mechanisms behind how polarized ion carriers interact with environmental signals are not well studied. Here, we use a physiology-relevant, physics-based mathematical model to reveal how ion carriers generate intracellular ion and voltage gradients. The model can discern the contribution of individual ion carriers to the intracellular pH gradient, electric potential, and water flux. We discover that an extracellular pH gradient leads to an intracellular pH gradient via chloride-bicarbonate exchangers, whereas an extracellular electric field leads to an intracellular electric potential gradient via passive potassium channels. In addition, mechanical-biochemical coupling can modulate actin distribution and flow, creating a biphasic dependence of cell speed on water flux. Moreover, we find that F-actin interaction with NHE alone can generate cell movement, even when other ion carriers are not polarized. Taken together, the model highlights the importance of cell ion dynamics in modulating cell migration and cytoskeletal dynamics. Published by the American Physical Society 2024

Single-cell analysis defines highly specific leukemia-induced neutrophils and links MMP8 expression to recruitment of tumor associated neutrophils during FGFR1 driven leukemogenesis

BackgroundLeukemias driven by activated, chimeric FGFR1 kinases typically progress to AML which have poor prognosis. Mouse models of this syndrome allow detailed analysis of cellular and molecular changes occurring during leukemogenesis. We have used these models to determine the effects of leukemia development on the immune cell composition in the leukemia microenvironment during leukemia development and progression.MethodsSingle cell RNA sequencing (scRNA-Seq) was used to characterize leukemia associated neutrophils and define gene expression changes in these cells during leukemia progression.ResultsscRNA-Seq revealed six distinct subgroups of neutrophils based on their specific differential gene expression. In response to leukemia development, there is a dramatic increase in only two of the neutrophil subgroups. These two subgroups show specific gene expression signatures consistent with neutrophil precursors which give rise to immature polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs). Analysis of gene expression in these precursor cells identified pathways that were specifically upregulated, the most pronounced of which involved matrix metalloproteinases Mmp8 and Mmp9, during leukemia progression. Pharmacological inhibition of MMPs using Ilomastat preferentially restricted in vitro migration of neutrophils from leukemic mice and led to a significantly improved survival in vivo, accompanied by impaired PMN-MDSC recruitment. As a result, levels of T-cells were proportionally increased. In clinically annotated TCGA databases, MMP8 was shown to act as an independent indicator for poor prognosis and correlated with higher neutrophil infiltration and poor pan-cancer prognosis.ConclusionWe have defined specific leukemia responsive neutrophil subgroups based on their unique gene expression profile, which appear to be the precursors of neutrophils specifically associated with leukemia progression. An important event during development of these neutrophils is upregulation MMP genes which facilitated mobilization of these precursors from the BM in response to cancer progression, suggesting a possible therapeutic approach to suppress the development of immune tolerance.

Almond fixed oil from Syagrus coronata (Mart.) Becc. has antinociceptive and anti-inflammatory potential, without showing oral toxicity in mice

Ethnopharmacological relevanceSyagrus coronata, a palm tree found in northeastern Brazil, popularly known as licuri, has socioeconomic importance for the production of vegetable oil rich in fatty acids with nutritional and pharmacological effects. Licuri oil is used in traditional medicine to treat inflammation, wound healing, mycosis, back discomfort, eye irritation, and other conditions. Aim of the studyThe study aimed to evaluate the antinociceptive, anti-inflammatory, and antipyretic effects of treatment with Syagrus coronata fixed oil (ScFO), as well as to determine the safety of use in mice. Materials and methodsInitially, the chemical characterization was performed by gas chromatography-mass spectrometry. Acute single-dose oral toxicity was evaluated in mice at a dose of 2000 mg/kg. Antinociceptive activity was evaluated through abdominal writhing, formalin, and tail dipping tests, and the anti-inflammatory potential was evaluated through the model of acute inflammation of ear edema, peritonitis, and fever at concentrations of 25, 50, and 100 mg/kg from ScFO. ResultsIn the chemical analysis of ScFO, lauric (43.64%), caprylic (11.7%), and capric (7.2%) acids were detected as major. No mortality or behavioral abnormalities in the mice were evidenced over the 14 days of observation in the acute toxicity test. ScFO treatment decreased abdominal writhing by 27.07, 28.23, and 51.78% at 25, 50, and 100 mg/kg. ScFO demonstrated central and peripheral action in the formalin test, possibly via opioidergic and muscarinic systems. In the tail dipping test, ScFO showed action from the first hour after treatment at all concentrations. ScFO (100 mg/kg) reduced ear edema by 63.76% and leukocyte and neutrophil migration and IL-1β and TNF-α production in the peritonitis test. ConclusionMice treated with ScFO had a reduction in fever after 60 min at all concentrations regardless of dose. Therefore, the fixed oil of S. coronata has the potential for the development of new pharmaceutical formulations for the treatment of pain, inflammation, and fever.

Triptolide regulates neutrophil function through the Hippo signaling pathway to alleviate rheumatoid arthritis disease progression

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by inflammatory changes in the joints, the etiology of which is unclear. It is now well established that regulated cell death (RCD) and migration of neutrophils play an important role in the pathogenesis of RA. Tripterygium wilfordii Hook.f (TwHF) is a total saponin extracted from the root of Tripterygium wilfordii Hook.f, a plant of the family Wesleyanaceae, which has strong anti-inflammatory and immunomodulatory effects and has been used as a basic drug in the clinical treatment of RA. Despite the good efficacy of TwHF treatment, the mechanism of action of TwHF remains unclear. Several studies have demonstrated that the drug tripterygium glycosides, in which TwHF is the main ingredient, has achieved excellent efficacy in the clinical treatment of RA. Investigations have also found that TwHF can affect cellular RCD, cell migration, cell proliferation, and the apoptosis-related Hippo signaling pathway. In this study, we first analyzed the RCD and migration differences of neutrophils in patients with RA through network pharmacology and transcriptome analysis. Subsequently, we used electron microscopy, immunofluorescence, and other methods to identify the RCD phenotype of neutrophils. In collagen-induced arthritis (CIA) model, we demonstrated that Triptolide (the main active ingredient in TwHF) could alleviate the progression of arthritis by reducing the bone destruction and the infiltration of neutrophils. Furthermore, in vitro experiments showed that Triptolide induced neutrophil apoptosis, inhibited the formation of neutrophil extracellular traps (NETs), and impeded the neutrophil migration process in a Hippo pathway-dependent manner. Taken together, these findings indicate that Triptolide has potential for treating RA and provide theoretical support for the clinical application of TwHF, as a traditional Chinese medicine, in RA.

LECs regulate neutrophil clearance through IL-17RC/CMTM4/NF-κB axis at sites of inflammation or infection

The lymphatic system plays a vital role in the regulation of tissue fluid balance and the immune response to inflammation or infection. The effects of lymphatic endothelial cells (LECs) on the regulation of neutrophil migration have not been well studied. In three murine models: imiquimod-induced skin inflammation, S. aureus-induced skin infection, and ligature-induced periodontitis, we show that numerous neutrophils migrate from inflamed or infected tissues to the draining lymph nodes via lymphatic vessels. Moreover, inflamed or infected tissues express a high level of IL-17A and TNF-α, simultaneously with a significant increase in the release of neutrophil attractors, including CXCL1, CXCL2, CXCL3, and CXCL5. Importantly, in vitro stimulation of LECs with IL-17A plus TNF-α synergistically promoted these chemokine secretion. Mechanistically, tetra-transmembrane protein CMTM4 directly binds to IL-17RC in LECs. IL-17A plus TNF-α stimulates CXC chemokine secretion by promoting NF-κB signaling. In contrast, knockdown of CMTM4 abrogates IL-17A plus TNF-α activated NF-κB signaling pathways. Lastly, the local administration of adeno-associated virus for CMTM4 in Prox1-CreERT2 mice, mediating LEC-specific overexpression of CMTM4, promotes the drainage of neutrophils by LECs and alleviates immune pathological responses. Thus, our findings reveal the vital role of LECs-mediated neutrophil attraction and clearance at sites of inflammation or infection.

Conditional epithelial sodium channel (ENaC) over-expression in C57Bl6 mouse lung triggers innate immune responses via activation of high mobility group box 1 (HMGB1) signaling

Background: One of the more sinister examples of a lung disease borne by chronic inflammation is cystic fibrosis (CF). Inherited mutations in the CFTR protein hinders the secretion of Cl−, depolarizing the membrane potential and enabling excessive Na+ flux across epithelial sodium channels (ENaCs). The mechanism by which these electrochemical imbalances contribute to chronic inflammation are unclear. Based on our preliminary observations, we hypothesize that hyperactive ENaC dysfunction plays a pivotal role in initiating sterile inflammation via activation of HMGB1 cytokine activity. Our research group has shown that high HMGB1 levels in CF sputum predicts incidence and recurrence of future acute pulmonary exacerbation. Methods: In support of this new line of investigation, we generated a conditional lung-ENaC overexpression model ( Dox-Scnn1b), which uniquely allows us to control the timing (and thus severity) of ENaC hyperactive dysfunction in C57Bl6 mice. Bronchoalveolar lavage fluid (BALF) and lung tissue samples were collected from WT and Dox-Scnn1b mice (± 625 mg/kg dox chow) in order to evaluate changes in transcript, protein, immune cell differentials, and lung injury following conditional lung ENaC overexpression. Student’s t-tests; ANOVA followed by post-hoc testing; and multivariate linear regression analysis (SigmaPlot 14.0 Systat Software) were used to evaluate statistical significance and determine whether ENaC feedforward signaling to HMGB1 effects pro-inflammatory signaling in lung epithelia. Results: qRT-PCR indicates that high dox chow (625 mg/kg) increased Scnn1b gene expression (encoding for β-ENaC subunit responsible for hyperactive channel dysfunction) by three-log fold over control fed mice, (n=6; p=0.01). Indeed, increase in Scnn1b transcript corresponded with significant increase in β-ENaC protein as detected by western blot analysis and amiloride sensitive current measurements. Importantly, Scnn1b overexpression correlated positively with increased HMGB1 protein in the lung (by 1.5 fold, p=.01 vs control; n= 6 from 2 independent studies) and % neutrophil migration. Dox induction of ENaC and HMGB1 also resulted in increased lung injury scores (from 0.24±0.1 to 0.45±0.06, n=3; p&lt;.01). Conclusions: Conditional lung ENaC overexpression mediates HMGB1 cytokine activity and closely recapitulates the sterile lung injury phenotype observed in CF patients. Significance: The mechanisms identified through this study can be targeted for new drug therapy, which is highly significant, since there are no effective therapies currently available for reversing lung inflammation. Funding: T35DK103596 (MZ) and R01HL137033 (MH). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Induction of TNFα by flavin adenine dinucleotide (FADH) protects neonatal C57Bl6 lungs from high oxygen induced lung injury

Background: Bronchopulmonary dysplasia (BPD) is a serious lung disease caused by oxidative stress, predominately affecting premature infants that require prolonged oxygen support. The co-factor flavin adenine dinucleotide (FADH) facilitates glutathione reductase (GR) enzymatic activity and increases the bioavailability of the antioxidant glutathione (GSH). As such, we hypothesized that intranasal delivery of FADH can improve redox homeostasis and attenuate lung injury following chronic high oxygen supplementation (0.85% FiO2) by altering pro-inflammatory signal transduction pathways in a C57Bl6 newborn mouse model for BPD. Methods: We used a prolonged hyperoxia-induced lung injury rodent model to recapitulate the clinical and histological changes present in BPD. Newborn mice were housed in FiO2 85% (hyperoxic) or 21% O2 (normoxic) from day of birth until post-natal day (PN) 14. FADH (7 μM) or saline (control) treatments were administered daily via intranasal insufflation on PN 14-21 in a final volume of 1.5μL/g body weight. BALF and lung tissue samples were collected and evaluated for redox stress, lung injury/development, and inflammation using standard immunohistological techniques, morphometric analysis, and standard molecular assays. BALF cytokines were measured using a flow cytometric approach (BioLegend). Two-dimensional cell migration assays were tracked via microscopy daily until 100% confluence reached; the ½ maximal peak values were evaluated to compare rate of wound closure following very low (2.5 ng/mL) TNFα or IL12 treatment. Transepithelial resistance and potential differences were measured using an EVOM device (World Precision Instrument) across human small airway epithelial cells, and equivalent short circuit currents (Isc) calculated in accordance with Ohm’s Law, where V=IR. Single data comparisons were performed using paired Student’s t-tests. Multiple comparisons were performed using ANOVA followed by post-hoc testing in Sigma Plot. Results: FADH protected neonatal lungs from high oxygen induced oxidative stress: GSH/GSSG Eh (a measure of oxidative stress) improved from -168.77 mV ± 3.64 mV to -179.10 mV ± 1.85 mV (n=5 BALF measurements). FADH also improved lung injury scores from 0.187±0.038 to 0.03±0.014 (p=0.005), decreased neutrophil migration (p&lt;0.001), and increased macrophages (p&lt;0.001) when compared to age-matched untreated pups. FADH-mediated increase in TNFα (and not IL12) significantly increased the rate of lung epithelial cell wound closure from [2.27±0.07 to 1.97±0.1 average days for ½ complete wound closure, n=6, p=0.01] and increased Isc from 6.5±.21 to 9.2±1.0 μA/cm2, n=3, p=0.03. Conclusions: Our findings indicate that FADH protects the preterm lung from hyperoxic injury by 1) increasing the bioavailability of GSH and 2) via TNFα signaling to increase the rate of wound closure and repair of epithelial cell function. Significances: The mechanisms identified through this study could be targeted as a potential adjunct therapy for BPD patients to attenuate high oxygen induced lung injury. Funding: Supported by R01HL137033 (MH). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Clinical significance and potential pathogenesis of VCAN in adult non-cystic fibrosis bronchiectasis: a retrospective study

BackgroundThe pathogenesis of adult non-cystic fibrosis (CF) bronchiectasis is complex, and the relevant molecular mechanism remains ambiguous. Versican (VCAN) is a key factor in inflammation through interactions with adhesion molecules. This study constructs a stable panoramic map of mRNA, reveals the possible pathogenesis of bronchiectasis, and provides new ideas and methods for bronchiectasis.MethodsPeripheral blood and tissue gene expression data from patients with bronchiectasis and normal control were selected by bioinformatics analysis. The expression of VCAN in peripheral blood and bronchial tissues of bronchiectasis were obtained by transcriptome sequencing. The protein expression levels of VCAN in serums were verified by the enzyme-linked immunosorbent assay (ELISA). The mRNA expression levels of VCAN in co-culture of Pseudomonas aeruginosa and bronchial epithelial cells were verified by real-time quantitative polymerase chain reaction (RT-qPCR). In addition, the biological function of VCAN was detected by the transwell assay.ResultsThe expression of VCAN was upregulated in the bronchiectasis group by sequencing analysis (P < 0.001). The expression of VCAN in the bronchial epithelial cell line BEAS-2B was increased in P. aeruginosa (P.a), which was co-cultured with BEAS-2B cells (P < 0.05). The concentration of VCAN protein in the serum of patients with bronchiectasis was higher than that in the normal control group (P < 0.05). Transwell experiments showed that exogenous VCAN protein induced the migration of neutrophils (P < 0.0001).ConclusionsOur findings indicate that VCAN may be involved in the development of bronchiectasis by increasing the migration of neutrophils and play an important role in bronchial pathogenesis.

Gram-negative anaerobes elicit a robust keratinocytes immune response with potential insights into HS pathogenesis.

Hidradenitis Suppurativa (HS) is a chronic autoinflammatory skin disease with activated keratinocytes, tunnel formation and a complex immune infiltrate in tissue. The HS microbiome is polymicrobial with an abundance of commensal gram-positive facultative (GPs) Staphylococcus species and gram-negative anaerobic (GNA) bacteria like Prevotella, Fusobacterium and Porphyromonas with increasing predominance of GNAs with disease severity. We sought to define the keratinocyte response to bacteria commonly isolated from HS lesions to probe pathogenic relationships between HS and the microbiome. Type strains of Prevotella nigrescens, Prevotella melaninogenica, Prevotella intermedia, Prevotella asaccharolytica, Fusobacterium nucleatum, as well as Staphylococcus aureus and the normal skin commensal Staphylococcus epidermidis were heat-killed and co-incubated with normal human keratinocytes. RNA was collected and analysed using RNAseq and RT-qPCR. The supernatant was collected from cell culture for protein quantification. Transcriptomic profiles between HS clinical samples and stimulated keratinocytes were compared. Co-staining of patient HS frozen sections was used to localize bacteria in lesions. A mouse intradermal injection model was used to investigate early immune recruitment. TLR4 and JAK inhibitors were used to investigate mechanistic avenues of bacterial response inhibition. GNAs, especially F. nucleatum, stimulated vastly higher CXCL8, IL17C, CCL20, IL6, TNF and IL36γ transcription in normal skin keratinocytes than the GPs S. epidermidis and S. aureus. Using RNAseq, we found that F. nucleatum (and Prevotella) strongly induced the IL-17 pathway in keratinocytes and overlapped with transcriptome profiles of HS patient clinical samples. Bacteria were juxtaposed to activated keratinocytes invivo, and F. nucleatum strongly recruited murine neutrophil and macrophage migration. Both the TLR4 and pan-JAK inhibitors reduced cytokine production. Detailed transcriptomic profiling of healthy skin keratinocytes exposed to GNAs prevalent in HS revealed a potent, extensive inflammatory response vastly stronger than GPs. GNAs stimulated HS-relevant genes, including many genes in the IL-17 response pathway, and were significantly associated with HS tissue transcriptomes. The close association of activated keratinocytes with bacteria in HS lesions and innate infiltration in murine skin cemented GNA pathogenic potential. These novel mechanistic insights could drive future targeted therapies.

Modulating effects of heat-killed and live Limosilactobacillus reuteri PSC102 on the immune response and gut microbiota of cyclophosphamide-treated rats.

In the present study, we investigated the potential immunomodulatory effects of heat-killed (hLR) and live Limosilactobacillus reuteri PSC102 (LR; formerly Lactobacillus reuteri PSC102) in RAW264.7 macrophage cells and Sprague-Dawley rats. RAW264.7 murine macrophage cells were stimulated with hLR and LR for 24 h. Cyclophosphamide (CTX)-induced immunosuppressed Sprague-Dawley rats were orally administered with three doses of hLR (L-Low, M-Medium, and H-High) and LR for 3 weeks. The phagocytic capacity, production of nitric oxide (NO), and expression of cytokines in RAW264.7 cells were measured, and the different parameters of immunity in rats were determined. hLR and LR treatments promoted phagocytic activity and induced the production of NO and the expression of iNOS, TNF-α, IL-1β, IL-6, and Cox-2 in macrophage cells. In the in vivo experiment, hLR and LR treatments significantly increased the immune organ indices, alleviated the spleen injury, and ameliorated the number of white blood cells, granulocytes, lymphocytes, and mid-range absolute counts in immunosuppressive rats. hLR and LR increased neutrophil migration and phagocytosis, splenocyte proliferation, and T lymphocyte subsets (CD4+, CD8+, CD45RA+, and CD28+). The levels of immune factors (IL-2, IL-4, IL-6, IL-10, IL-12A, TNF-α, and IFN-γ) in the hLR and LR groups were upregulated compared with those in the CTX-treatment group. hLR and LR treatments could also modulate the gut microbiota composition, thereby increasing the relative abundance of Bacteroidetes and Firmicutes but decreasing the level of Proteobacteria. hLR and LR protected against CTX-induced adverse reactions by modulating the immune response and gut microbiota composition. Therefore, they could be used as potential immunomodulatory agents.

Stat3 Regulates Developmental Hematopoiesis and Impacts Myeloid Cell Function via Canonical and Non-Canonical Modalities

Introduction: Signal transducer and activator of transcription (STAT) 3 is extensively involved in the development, homeostasis, and function of immune cells, with STAT3 disruption associated with human immune-related disorders. The roles ascribed to STAT3 have been assumed to be due to its canonical mode of action as an inducible transcription factor downstream of multiple cytokines, although alternative noncanonical functional modalities have also been identified. The relative involvement of each mode was further explored in relevant zebrafish models. Methods: Genome editing with CRISPR/Cas9 was used to generate mutants of the conserved zebrafish Stat3 protein: a loss of function knockout (KO) mutant and a mutant lacking C-terminal sequences including the transactivation domain (ΔTAD). Lines harboring these mutations were analyzed with respect to blood and immune cell development and function in comparison to wild-type zebrafish. Results: The Stat3 KO mutant showed perturbation of hematopoietic lineages throughout primitive and early definitive hematopoiesis. Neutrophil numbers did not increase in response to lipopolysaccharide (LPS) or granulocyte colony-stimulating factor (G-CSF) and their migration was significantly diminished, the latter correlating with abrogation of the Cxcl8b/Cxcr2 pathway, with macrophage responses perturbed. Intriguingly, many of these phenotypes were not shared by the Stat3 ΔTAD mutant. Indeed, only neutrophil and macrophage development were disrupted in these mutants with responsiveness to LPS and G-CSF maintained, and neutrophil migration actually increased. Conclusion: This study has identified roles for zebrafish Stat3 within hematopoietic stem cells impacting multiple lineages throughout primitive and early definitive hematopoiesis, myeloid cell responses to G-CSF and LPS and neutrophil migration. Many of these roles showed conservation, but notably several involved noncanonical modalities, providing additional insights for relevant diseases.

The Role of Cannabinoid-1 Receptor Ligands in the Ovalbumin-Induced Mouse Model of Allergic Asthma: Is It Related to Transient Receptor Potential Vanilloid-1 Channels?

Objectives: The aim of this study was to investigate the role of cannabinoid (CB1) receptors on airway inflammation and hypersensitivity in allergic asthma and the potential interactions with TRPV1 channels. Materials and Methods: BALB/c mice were sensitized and provoked with ovalbumin to create a model of allergic asthma. CB1 selective agonist arachidonoyl 2'-chloroethylamide (ACEA) was administered intraperitoneally at doses of 0.5, 3, and 5 mg/kg. Receptor antagonism studies were performed utilizing selective CB1 antagonists AM251 at a dose of 3 mg/kg. TRPV1 channel was selectively blocked by capsazepine at a dose of 2.5 mg/kg. Penh values were recorded in vivo by a whole-body plethysmograph under methacholine challenge. Inflammatory cell count was performed in bronchoalveolar lavage fluid (BALF). Serum levels of proinflammatory cytokines were measured by Enzyme-Linked ImmunoSorbent Assay (ELISA). Inflammation in the lung tissue was scored histopathologically. Statistical significance was determined using one-way analysis of variance or Kruskal-Wallis test and expressed as p<0.05. Results: In sensitized animals, provocation with inhaled ovalbumin increased Penh values, serum interleukin (IL)-4, IL-5, IL-13 levels, eosinophil, neutrophil, lymphocyte, macrophage counts in BALF, and inflammation in the lung tissue. ACEA applications did not significantly alter Penh values, BALF inflammatory cell levels, and histological changes related to inflammation in the lung tissue according to the disease group; however, only at a dose of 5 mg/kg, it reduced the levels of the inflammatory cytokine IL-4. AM251 decreased Penh values, eosinophil and neutrophil migration in BALF, and inflammation score of lung tissue compared with the disease group. Although BALF inflammatory cell levels and Penh values were higher in the AM251+ACEA group than in the AM251 group, the differences were insignificant. In the CPZ+ACEA group, Penh values were significantly higher, and serum IL-4 and IL-13 levels and BALF eosinophil counts were lower than that in the CPZ group. Conclusions: This study demonstrated an important role of the CB1 receptors in allergic asthma. CB1 antagonism reduced airway hyperresponsiveness and inflammation and showed immunomodulatory effects. The effect of the CB1 agonist ACEA on asthma does not appear to be related to TRPV1 channels.

Regulation of ICAM-1 in human neutrophils

Abstract Intercellular cell adhesion molecule 1 (ICAM-1) is a cell surface glycoprotein with a vital role in the immune response to pathogens. The expression pattern of ICAM-1 is wide ranging, encompassing endothelial cells, epithelial cells, and neutrophils. Recent work has characterized the role of ICAM-1 in murine neutrophils, but the function of human neutrophil ICAM-1 is incompletely understood. Herein, we investigated the expression and role of ICAMs in human neutrophils in vitro and in vivo. Our findings show clear expression of ICAM-1, -3, and -4 on peripheral blood–derived neutrophils and demonstrate that the pathogen-associated molecular pattern lipoteichoic acid is an inducer of ICAM-1 expression in vitro. In vivo, neutrophils obtained from the pleural cavity of patients with a parapneumonic effusion display enhanced expression of ICAM-1 compared with peripheral blood– and oral cavity–derived neutrophils. Moreover, migration of peripheral blood–derived neutrophils across endothelial cells can upregulate neutrophil ICAM-1 expression. These findings indicate that pathogen-associated molecular patterns and/or cytokines, alongside transmigration, enhance neutrophil ICAM-1 expression at sites of inflammation. Mechanistically, we observed that ICAM-1high neutrophils display elevated S. aureus phagocytic capacity. However, unlike murine neutrophils, ICAM-1 intracellular signaling in human neutrophils was not essential for phagocytosis of Staphylococcus aureus and reactive oxygen species generation. Taken together, these results have important implications for the regulation of neutrophil-mediated pathogen clearance.