Number Of Neutrophils Research Articles

RLS-0071, a novel anti-inflammatory agent, significantly reduced inflammatory biomarkers in a randomised human evaluation of mechanisms and safety study.

This study was a randomised, double-blind, placebo-controlled study intended to establish the translatability of the RLS-0071 mechanisms of action from animal disease models to humans by inhibiting neutrophil-mediated inflammation at the tissue level and major inflammatory biomarkers. We hypothesised that RLS-0071 inhibits a temporary neutrophil-mediated inflammation in the lungs induced by inhalation of low-dose lipopolysaccharide (LPS) in healthy participants. Participants were randomised to one of three arms to receive inhaled LPS followed by three doses of either low-dose (10 mg·kg-1) or high-dose (120 mg·kg-1 loading dose followed by two doses of 40 mg·kg-1) RLS-0071 i.v. or placebo (saline) every 8 h. Biomarkers evaluating inflammatory responses, with absolute neutrophil counts in induced sputum as the primary end-point, were collected before and at 6 and 24 h after LPS challenge. Active treatment with RLS-0071 showed a similar safety profile to participants receiving placebo. RLS-0071 significantly decreased the numbers of neutrophils in sputum at 6 h post LPS by approximately half (p=0.04). Neutrophil effectors myeloperoxidase, neutrophil elastase and interleukin-1β in sputum were also significantly decreased at 6 h for RLS-0071 compared with placebo. Several biomarkers showed trends suggesting sustained decreases for RLS-0071 versus placebo at 24 h. This clinical trial demonstrated that RLS-0071 was safe and well tolerated and modulated neutrophil-mediated inflammation in humans after inhaled LPS challenge, consistent with results from prior animal model studies.

Modelling lung infection with Klebsiella pneumoniae after murine traumatic brain injury

Pneumonia is a common comorbidity in patients with severe traumatic brain injury (TBI), and is associated with increased morbidity and mortality. In this study, we established a model of intratracheal Klebsiella pneumoniae administration in young adult male and female mice, at 4 days following an experimental TBI, to investigate how K. pneumoniae infection influences acute post-TBI outcomes. A dose-response curve determined the optimal dose of K. pneumoniae for inoculation (1 x 10^6 colony forming units), and administration at 4 days post-TBI resulted in transient body weight loss and sickness behaviors (hypoactivity and acute dyspnea). K. pneumoniae infection led to an increase in pro-inflammatory cytokines in serum and bronchoalveolar lavage fluid at 24 h post-infection, in both TBI and sham (uninjured) mice. By 7 days, when myeloperoxidase + neutrophil numbers had returned to baseline in all groups, lung histopathology was observed with an increase in airspace size in TBI + K. pneumoniae mice compared to TBI + vehicle mice. In the brain, increased neuroinflammatory gene expression was observed acutely in response to TBI, with an exacerbated increase in Ccl2 and Hmox1 in TBI + K. pneumoniae mice compared to either TBI or K. pneumoniae alone. However, the presence of neuroinflammatory immune cells in the injured brain, and the extent of damage to cortical and hippocampal brain tissue, was comparable between K. pneumoniae and vehicle-treated mice by 7 days. Examination of the fecal microbiome across a time course did not reveal any pronounced effects of either injury or K. pneumoniae on bacterial diversity or abundance. Together, these findings demonstrate that K. pneumoniae lung infection after TBI induces an acute and transient inflammatory response, primarily localized to the lungs with some systemic effects. However, this infection had minimal impact on secondary injury processes in the brain following TBI. Future studies are needed to evaluate the potential longer-term consequences of this dual-hit insult.

The Elevated Inflammatory Status of Neutrophils Is Related to In-Hospital Complications in Patients with Acute Coronary Syndrome and Has Important Prognosis Value for Diabetic Patients.

Despite neutrophil involvement in inflammation and tissue repair, little is understood about their inflammatory status in acute coronary syndrome (ACS) patients with poor outcomes. Hence, we investigated the potential correlation between neutrophil inflammatory markers and the prognosis of ACS patients with/without diabetes and explored whether neutrophils demonstrate a unique inflammatory phenotype in patients experiencing an adverse in-hospital outcome. The study enrolled 229 ACS patients with or without diabetes. Poor evolution was defined as either death, left ventricular ejection fraction (LVEF) <40%, Killip Class 3/4, ventricular arrhythmias, or mechanical complications. Univariate and multivariate analyses were employed to identify clinical and paraclinical factors associated with in-hospital outcomes. Neutrophils isolated from fresh blood were investigated using qPCR, Western blot, enzymatic assay, and immunofluorescence. Poor evolution post-myocardial infarction (MI) was associated with increased number, activity, and inflammatory status of neutrophils, as indicated by significant increase of Erythrocyte Sedimentation Rate (ESR), C-reactive protein (CRP), fibrinogen, interleukin-1β (IL-1β), and, interleukin-6 (IL-6). Among the patients with complicated evolution, neutrophil activity had an important prognosis value for diabetics. Neutrophils from patients with unfavorable evolution revealed a pro-inflammatory phenotype with increased expression of CCL3, IL-1β, interleukin-18 (IL-18), S100A9, intracellular cell adhesion molecule-1 (ICAM-1), matrix metalloprotease (MMP-9), of molecules essential in reactive oxygen species (ROS) production p22phox and Nox2, and increased capacity to form neutrophil extracellular traps. Inflammation is associated with adverse short-term prognosis in acute ACS, and inflammatory biomarkers exhibit greater specificity in predicting short-term outcomes in diabetics. Moreover, neutrophils from patients with unfavorable evolution exhibit distinct inflammatory patterns, suggesting that alterations in the innate immune response in this subgroup may exert detrimental effects on disease progression.

Neutrophil-derived PAD4 induces citrullination of CKMT1 exacerbates mucosal inflammation in inflammatory bowel disease.

Peptidyl arginine deiminase 4 (PAD4) plays a pivotal role in infection and inflammatory diseases by facilitating the formation of neutrophil extracellular traps (NETs). However, the substrates of PAD4 and its exact role in inflammatory bowel disease (IBD) remain unclear. In this study, we employed single-cell RNA sequencing (scRNA-seq) and substrate citrullination mapping to decipher the role of PAD4 in intestinal inflammation associated with IBD. Our results demonstrated that PAD4 deficiency alleviated colonic inflammation and restored intestinal barrier function in a dextran sulfate sodium (DSS)-induced colitis mouse model. scRNA-seq analysis revealed significant alterations in intestinal cell populations, with reduced neutrophil numbers and changes in epithelial subsets upon PAD4 deletion. Gene expression analysis highlighted pathways related to inflammation and epithelial cell function. Furthermore, we found that neutrophil-derived extracellular vesicles (EVs) carrying PAD4 were secreted into intestinal epithelial cells (IECs). Within IECs, PAD4 citrullinates mitochondrial creatine kinase 1 (CKMT1) at the R242 site, leading to reduced CKMT1 protein stability via the autophagy pathway. This action compromises mitochondrial homeostasis, impairs intestinal barrier integrity, and induces IECs apoptosis. IEC-specific depletion of CKMT1 exacerbated intestinal inflammation and apoptosis in mice with colitis. Clinical analysis of IBD patients revealed elevated levels of PAD4, increased CKMT1 citrullination, and decreased CKMT1 expression. In summary, our findings highlight the crucial role of PAD4 in IBD, where it modulates IECs plasticity via CKMT1 citrullination, suggesting that PAD4 may be a potential therapeutic target for IBD.

Enhanced hepatotoxicity in zebrafish due to co-exposure of microplastics and sulfamethoxazole: Insights into ROS-mediated MAPK signaling pathway regulation

The combined pollution of microplastics (MPs) and sulfamethoxazole (SMZ) often occurs in aquatic ecosystems, posing a serious threat to animal and human health. However, little is known about the liver damage caused by the single or co-exposure of MPs and SMZ, and its specific mechanisms are still poorly understood. In this study, we investigated the effects of co-exposure to 20 μm or 80 nm MPs and SMZ in both larval and adult zebrafish models. Firstly, we observed a significant decrease in the number of hepatocytes and the liver damage in larval zebrafish worsened following co-exposure to SMZ and MPs. Additionally, the number of macrophages and neutrophils decreased, while the expression of inflammatory cytokines and antioxidant enzyme activities increased after co-exposure in larval zebrafish. Transcriptome analysis revealed significant changes in gene expression in the co-exposed groups, particularly in processes related to oxidation-reduction, inflammatory response, and the MAPK signaling pathway in the liver of adult zebrafish. Co-exposure of SMZ and MPs also promoted hepatocyte apoptosis and inhibited proliferation levels, which was associated with the translocation of Nrf2 from the cytoplasm to the nucleus and an increase in protein levels of Nrf2 and NF-kB p65 in the adult zebrafish. Furthermore, our pharmacological experiments demonstrated that inhibiting ROS and blocking the MAPK signaling pathway partially rescued the liver injury induced by co-exposure both in larval and adult zebrafish. In conclusion, our findings suggest that co-exposure to SMZ and MPs induces hepatic dysfunction through the ROS-mediated MAPK signaling pathway in zebrafish. This information provides novel insights into the potential environmental risk of MPs and hazardous pollutants co-existence in aquatic ecosystems.

Abstract PO5-13-08: Impact of systemic inflammation markers in response to neoadjuvant pembrolizumab and chemotherapy in triple-negative breast cancer - a retrospective analysis

Abstract Background: Immune checkpoint inhibitors (ICIs) have revolutionized the treatment landscape for triple-negative breast cancer (TNBC). Systemic inflammation has been linked to cancer development and overall poor outcomes. Routine blood parameters have been investigated as potential inflammatory biomarkers in patients (pts) with various types of cancer, such as the derived NLR (neutrophils/(leucocytes-neutrophils) ratio (dNLR). A high dNLR has been associated with worse survival in several types of cancer. Specifically, it has been linked to lower pathologic complete response (pCR) rates after neoadjuvant chemotherapy (CTx). We investigated the association between systemic inflammation markers (dNLR, LIPI score and platelet-to-lymphocyte ratio [PLR]) and pCR in early TNBC pts treated with CTx + pembrolizumab (Pemb). Methods: Retrospective analysis of pts with early TNBC treated with Pemb + CTx from April 2022 to March 2023. dNLR was estimated from analytical values of peripheral blood collected before treatment (baseline). dNLR was calculated as the ratio of the absolute neutrophil number to the difference between absolute total leukocyte and absolute neutrophil counts. Univariate and multivariate logistic regression analyses were used to explore the association of dNLR with main clinical characteristics and dNLR capability (distributed as a continuous variable, using median cut-off) to predict pCR. Results: The study included 86 TNBC pts with a median age of 51 years (IQR: 42.2 – 56-7). Most pts had stage II disease (64%) and presented grade 3 tumours (n=66; 78.5%). HER2 low tumours represented 27% (n=23) of the cohort. Germline mutations were present in 20 pts (23%) with the following distribution: BRCA1 (n=14), BRCA 2 (n=5) and PALB2 (n=1). The median stromal tumor infiltrating lymphocytes (TILs) was 20% (IQR: 10-30%). The median Ki67 was 70% (IQR:50%-80%). All pts received Pemb. The majority of pts received carboplatin plus paclitaxel, followed by EC90 (n=77 (90%), while 10% (n=9) did not receive anthracyclines. Data concerning surgical outcomes was available in 80 pts. Pathological complete response rate was 61.2% (n=49). Pts achieving pCR presented significantly higher TILs (p&amp;lt; 0.01). Residual cancer burden (RCB) class (n=80) was distributed as follows: 0: 61% (n=49); I: 13% (n=10); II: 20% (n=16); III: 1% (n=1) and non-assigned: 5% (n=4). In pts with germline mutations (n=20), the pCR rate was 85% (n=17). Median dNLR at baseline was 1.30 (interquartile range (IQR): 0.99 – 1.86). High baseline dNLR levels considered a continuous variable was associated with a higher likelihood of achieving a pCR in univariate (OR: 2.59; 95% CI: 1.01–6.6; p-value = 0.046) but not in multivariate (OR: 2.33; 95%; CI: 0.85–6.33; p-value = 0.097) logistic regression analysis (adjusted for stage and histologic grade). High baseline dNLR, defined by the median cut-off, was associated with an increased likelihood of achieving pCR in both univariate (OR: 3.85; 95% CI: 1.47–10.1; p-value = 0.006) and multivariate (OR: 3.72; 95% CI: 1.28–10.8; p-value = 0.016) logistic regression analysis (adjusted for stage and histologic grade). Conclusion: In this real-life cohort of early TNBC pts treated with Pemb and CTx we found similar pCR rates (61.2%) to the ones reported in the KN522 trial. No association between PLR or LIPI score with pCR was evidenced. High baseline dNLR (assessed as a continuous variable or by the median cut-off) was associated with a higher likelihood of pCR in the univariate analysis. In the multivariate analysis, only high baseline dNLR defined by the median cut-off retained an association with pCR after stage and histologic grade adjustment. Despite several limitations, these exploratory data provide initial evidence of a potential association between dNLR values and independent prediction of pCR. Further research to assess the role of dNLR as a predictive marker for pCR in early TNBC pts treated with CTx + immunotherapy is needed. Citation Format: Martina Spotti, Elie Rassy, Alessandro Viansone, Fiona Pham, Layal Rached, Barbara Pistilli, Charles-Antoine Dutertre, Joana Mourato Ribeiro. Impact of systemic inflammation markers in response to neoadjuvant pembrolizumab and chemotherapy in triple-negative breast cancer - a retrospective analysis [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-13-08.

Effects of Exercise Therapy on Circadian Rhythm Regulation of Neutrophils

Abstract Background: Physical inactivity is recognized as a risk factor for numerous common illnesses, while exercise has been shown to be beneficial. Neutrophils are the first line of cell-mediated defense, with characterized by circadian rhythms. The liver is metabolically active organ that is strongly influenced by circadian regulation. The effects of exercise-induced circadian changes may modify the neutrophils phenotype and function. Methods: Male mice undergoing a four-week treadmill regimen for 1h at ZT3(3h after lights on). Bone marrow, blood and liver tissue were analyzed at different time points. Circadian genes and neutrophil subpopulations were assessed. Results: The circulating neutrophil numbers were fluctuated according to a circadian pattern with a peak at ZT3 and a nadir at ZT15. Rhythmicity analysis revealed that the circadian amplitude was increased, but the period and phase were unaltered. Mice subjected to exercise had fewer immature and higher mature neutrophils in bone marrow at ZT3. The expression of clock-related genes in liver, including Arntl and Clock, increased at ZT3, while others, like Per1 were decreased. The number of aged neutrophil follows diurnal patterns with a peak at ZT3, and exhibited a greater percentage and number of neutrophils with an aging phenotype in blood at Exercise group. Summary: Exercise modulates circadian-dependent neutrophils quiescence, promotes maturation of myeloid neutrophils and driven circulating neutrophil aging phenotype.

Mechanism of total glucosides of White Paeony Capsules in ameliorating acute lung injury based on NLRP3 inflammasome

This study deciphered the ameliorating effect and molecular mechanism of the total glucosides of White Paeony Capsules(TGP) in the treatment of mice model with acute lung injury(ALI) via NOD-like receptor thermal protein domain associated protein 3(NLRP3) signaling pathway of the inflammasome. The study established an inflammasome activation model of primed bone marrow-derived macrophages(BMDMs), and its molecular mechanism was investigated by Western blot(WB), immunofluorescence staining, enzyme-linked immunosorbent assay(ELISA), and flow cytometry. C57BL/6J mice were randomly divided into a blank control group, a TGP group, a model group(LPS group), LPS+low-and high-dose TGP groups, LPS+MCC950 group, and LPS+MCC950+TGP group, with eight mice per group. The ALI model was induced in mice. Finally, bronchoalveolar lavage fluid(BALF) and lung tissue were collected. Lung index and lung weight wet-to-dry ratio were determined for each group of mice. The pathological changes in lung tissue were observed through hematoxylin-eosin(HE) staining. The number of neutrophils in the BALF of each group was detected using flow cytometry. The levels of interleukin(IL)-1β, IL-6, and tumor necrosis factor(TNF)-α in the BALF were determined by ELISA. The expressions of IL-1β, IL-18, IL-6, and TNF-α in the lung tissue were determined by real-time quantitative PCR(RT-qPCR). This study demonstrated that TGP dramatically blocked the activation of the NLRP3 inflammasome by inhibiting the production of upstream mitochondrial reactive oxygen species(mtROS) and the subsequent oligomerization of apoptosis-associated specks(ASC). Additionally, in the ALI mice model, compared with the blank control group, the model group showed alveolar structure rupture, thic-kening of alveolar septa, and dramatically increased lung index, lung weight wet-to-dry ratio in lung tissue, neutrophil count, and inflammatory factor levels. Compared with the model group, the pathological morphology of lung tissue was significantly ameliorated in the TGP and MCC950 groups, and the lung index and lung weight wet-to-dry ratio were significantly reduced. Neutrophil counts were reduced, and levels of inflammatory factors were significantly downregulated. Notably, compared with the MCC950 group, there was no significant difference in effect in the MCC950+TGP group. Collectively, the study reveals that TGP may ameliorate ALI in mice by inhibiting the activation of NLRP3 inflammasome, providing a safe and effective drug candidate for the prevention or treatment of ALI/ARDS.

P311 KO Mice are Protected from Experimentally Induced Lung Fibrosis

Pulmonary fibrosis (PF) is a fatal chronic interstitial lung disease and one of the most irreversible forms of tissue/organ fibrosis. Idiopathic pulmonary fibrosis is a very progressive disease accompanied by inflammatory damage with a median survival of less than 5 years. Etiology of IPF is still elusive with potential reasons being genetic predisposition and environmental exposures including particulates, radiation, and SARS-CoV-2. Recent studies indicate that about 50% of COVID19 associated acute respiratory distress syndrome survivors develop PF. There are very limited treatment options with no curative therapies available for PF apart from invasive lung transplantation. P311 is an 8 kDa protein previously shown to have a key role in lung regeneration. As P311 overexpression in fibroblasts induced myofibroblast phenotype, we hypothesized that P311 has a role in tissue fibrosis. We induced PF by intra-tracheally instilling bleomycin (BL) in P311 knockout (KO) mice and wild type (WT, C57BL/6) control mice and collected lungs after 2-5 weeks. P311 KO mice showed significantly less fibrosis. After intra-tracheal instillation of BL, the lungs of P311 KO mice (D21) had significantly reduced number of myofibroblasts as indicated by reduced SM α-actin expression and collagen deposition as indicated by Masson trichrome staining compared to their WT counterparts. We further observed reduced levels of TGF-β1-3 and Smad-2 and -3 along with decreased epithelial to mesenchymal transdifferentiation markers in the lungs of bleomycin treated P311 KOs compared to WT controls. Further bronchoalveolar lavage fluid (BALF) was collected (D14) and utilized to determine the pulmonary inflammation by determining the total and different immune cell populations in the BALF and lung samples by FACS analysis. Even though we saw a significant increase in the BALF cellularity, we did not observe significant changes in T-cell, macrophage, and neutrophil numbers between WT and P311KOs. However, lung cell isolates showed significantly increased CD3 and CD4 positive cells indicating increased T-cells and helper T-cells in fibrotic P311KO lungs compared to WT lungs. In conclusion, bleomycin administration resulted in lung fibrosis in WT mice, but P311 KO mice are protected. This study was partially supported by research funding to KB, from American Lung Association, DA-196629-N. 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.

Helicobacter pylori CagA Promotes the Formation of Gallstones by Increasing the Permeability of Gallbladder Epithelial Cells.

The formation of gallstones is often accompanied by chronic inflammation, and the mechanisms underlying inflammation and stone formation are not fully understood. Our aim is to utilize single-cell transcriptomics, bulk transcriptomics, and microbiome data to explore key pathogenic bacteria that may contribute to chronic inflammation and gallstone formation, as well as their associated mechanisms. scRNA-seq data from a gallstone mouse model were extracted from the Gene Expression Omnibus (GEO) database and analyzed using the FindCluster() package for cell clustering analysis. Bulk transcriptomics data from patients with gallstone were also extracted from the GEO database, and intergroup functional differences were assessed using GO and KEGG enrichment analysis. Additionally, 16S rRNA sequencing was performed on gallbladder mucosal samples from asymptomatic patients with gallstone (n = 6) and liver transplant donor gallbladder mucosal samples (n = 6) to identify key bacteria associated with stone formation and chronic inflammation. Animal models were constructed to investigate the mechanisms by which these key pathogenic bacterial genera promote gallstone formation. Analysis of scRNA-seq data from the gallstone mouse model (GSE179524) revealed seven distinct cell clusters, with a significant increase in neutrophil numbers in the gallstone group. Analysis of bulk transcriptomics data from patients with gallstone (GSE202479) identified chronic inflammation in the gallbladder, potentially associated with dysbiosis of the gallbladder microbiota. 16S rRNA sequencing identified Helicobacter pylori as a key bacterium associated with gallbladder chronic inflammation and stone formation. Dysbiosis of the gallbladder mucosal microbiota is implicated in gallstone disease and leads to chronic inflammation. This study identified H. pylori as a potential key mucosal resident bacterium contributing to gallstone formation and discovered its key pathogenic factor CagA, which causes damage to the gallbladder mucosal barrier. These findings provide important clues for the prevention and treatment of gallstones.

ANGPTL2 knockdown induces autophagy to relieve alveolar macrophage pyroptosis by reducing LILRB2-mediated inhibition of TREM2.

Acute lung injury (ALI) is featured with a robust inflammatory response. Angiopoietin-like protein 2 (ANGPTL2), a pro-inflammatory protein, is complicated with various disorders. However, the role of ANGPTL2 in ALI remains to be further explored. The mice and MH-S cells were administrated with lipopolysaccharide (LPS) to evoke the lung injury invivo and invitro. The role and mechanism of ANGPTL was investigated by haematoxylin-eosin, measurement of wet/dry ratio, cell count, terminal deoxynucleotidyl transferase deoxyuridine triphosphate (dUTP) nick end labeling, reverse transcription quantitative polymerase chain reaction, immunofluorescence, enzyme-linked immunosorbent assay, detection of autophagic flux and western blot assays. The level of ANGPTL2 was upregulated in lung injury. Knockout of ANGPTL2 alleviated LPS-induced pathological symptoms, reduced pulmonary wet/dry weight ratio, the numbers of total cells and neutrophils in BALF, apoptosis rate and the release of pro-inflammatory mediators, and modulated polarization of alveolar macrophages in mice. Knockdown of ANGPTL2 downregulated the level of pyroptosis indicators, and elevated the level of autophagy in LPS-induced MH-S cells. Besides, downregulation of ANGPTL2 reversed the LPS-induced the expression of leukocyte immunoglobulin (Ig)-like receptor B2 (LILRB2) and triggering receptor expressed on myeloid cells 2 (TREM2), which was reversed by the overexpression of LILRB2. Importantly, knockdown of TREM2 reversed the levels of autophagy- and pyroptosis-involved proteins, and the contents of pro-inflammatory factors in LPS-induced MH-S cells transfected with si ANGPTL2, which was further inverted with the treatment of rapamycin. Therefore, ANGPTL2 silencing enhanced autophagy to alleviate alveolar macrophage pyroptosis via reducing LILRB2-mediated inhibition of TREM2.

Neutrophils orchestrate early cardiac remodeling after cardiac pressure overload

Cardiac pressure overload is a chronic condition where the left ventricle undergoes pathological hypertrophy and fibrosis ultimately causing heart failure. Increased myocardial stretch in left ventricular pressure overload initiates activation of an inflammatory and fibrotic response within resident cells leading to infiltration of immune cells. Neutrophils and monocytes are among the first responders during cardiac injury. While the role of monocytes and macrophages in pressure overload has been somewhat elucidated by multiple groups, including our lab, the role of neutrophils in chronic cardiac injury such as pressure overload is still unclear. We hypothesized that, like acute ischemic injury, neutrophils infiltrate to the heart early in pressure overload and initiate an inflammatory cascade which worsens cardiac dysfunction after TAC and that depletion of neutrophils in the first week of TAC would improve cardiac function. Our published single cell RNAseq dataset of immune cells (CD45+) cells from sham and TAC heart at day (D) 7 shows a distinct clustering of neutrophils with S100a9 (34-fold) , S100a8 (31-fold) , Retnlg (9-fold) , Il1b (5-fold) , and Slpi (5-fold) as top 5 differentially expressed genes (DEGs). Geneset enrichment analysis of top 58 DEGs (≥1.5-folds), shows significant association with pathways such as innate immune system, neutrophil degranulation, and signaling by interleukins by Reactome 2022 pathway. Using a murine model of transaortic constriction (TAC) to induce left ventricular pressure overload, we evaluated cardiac neutrophil counts by flow cytometry over the first week of TAC at D 2, 4 and 7. We observed that neutrophils (CD45+Ly6G+CD11b+) numbers consistently increase until D4, with a 7-fold increase at D2 to a 17-fold increase at D4 before returning to sham levels by D7. Using antibody (Anti Gr-1, 4 ug/g) mediated depletion of neutrophils, we observed that neutrophil depletion showed a protective effect in females compared to isotype controls with decreased cardiac hypertrophy and improved ejection fraction; while in male mice no change was observed between isotype and antibody treated groups. In conclusion, our data show that neutrophils peak early in pressure overload and orchestrate early cardiac remodeling with a potential for a sexually dimorphic role. We acknowledge funding from National Institute of Health under the awards numbers HL155993 and HL160665. 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.

Defining the role of PSTPIP2 in neutrophil inflammatory function

Abstract Our lab and others have found that neutrophils isolated from Pstpip2cmo mice, that are deficient in proline-serine-threonine phosphatase-interacting protein 2 (PSTPIP2), display a hyperinflammatory phenotype with increased IL-1b and ROS secretion following stimulation. The hyperactive neutrophil phenotype is critical to the spontaneous development of an autoinflammatory disorder called chronic multifocal osteomyelitis. However, there are gaps in our understanding of the underlying mechanism that leads to the observed phenotype in Pstpip2cmo mice which could further our understanding of neutrophil biology. We first infected WT and Pstpip2cmo mice with P. aeruginosa to elucidate the importance of PSTPIP2 in vivo. 24-hours post infection, Pstpip2cmo mice had significantly lower bacterial burden compared to WT mice. We found increased neutrophils and monocytes in the bronchial alveolar fluid (BAL) of infected Pstpip2cmo mice, and these neutrophils are lower in side-scatter measured by flow cytometry. Under homeostatic conditions, we observed higher numbers of neutrophils in the bone marrow, blood, and spleen of Pstpip2cmo mice, and more granulocyte progenitors. In addition to elevated cell numbers, we found increased IL-1β secretion NETosis compared to WT mice. Together these data suggest that PSTPIP2 plays a critical role in restraining neutrophilic inflammatory response to bacterial infection and affects granulopoiesis in naïve mice.

Pengaruh Hydrogel Acemannan dengan Konsentrasi 25%, 50%, 75% terhadap Jumlah Neutrofil pada Tikus Wistar Periodontitis yang Diinduksi Aloksan

Neutrophils occur in periodontitis, an infection of the periodontal tissue that may increase the risk of diabetes. Because of its excellent physicochemical properties and biological capabilities, hydrogel is a promising biomaterial for treating periodontal disease. This study consisted of four groups of Acemannan hydrogel 25%, 50%, 75%, and the Federer formula was used to determine the sample size and six replicate experiments were performed for each group to form a positive control group. Considering the investigation's conclusions, in the acemannan hydrogel administration group, the average ± SD levels of neutrophils in samples on day 3 were 25%, 50%, and 75%, and the positive control group was 3.08 ± 0.736. 2.46 ± 0.459; 1.54 ± 0.510; 1.17 ± 0.258. This value decreased to 1.83 ± 0.258 by day 5 were 1.29 ± 0.459; 0.50±0.447; 0.21 ± 0.292. As a result of the Kruskal-Wallis statistical test, there was a significant difference in the average number of neutrophils after administering 25%, 50%, and 75% Acemannan hydrogel and the positive control group to rats with alloxan-induced Wistar periodontitis on the third and fifth days. The study's findings suggest that 75% of acemannan hydrogel is the most effective concentration for reducing neutrophils

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.

Differences in Airway Remodeling and Emphysematous Lesions between Rats Exposed to Smoke from New-Type and Conventional Tobacco Varieties.

Genes from Perilla frutescens and Ocimum basilicum were introduced into N. tabacum L. var. HHY via distant hybridization, and the new-type tobacco varieties "Zisu" and "Luole" were developed, with noticeable differences in chemical composition. Smoking is the leading cause of chronic obstructive pulmonary disease (COPD), and its pathogenesis is complex. In the present study, 48 male Sprague-Dawley (SD) rats were randomly divided into four groups, namely, the control, "HHY", "Zisu" and "Luole", and then exposed to fresh air/cigarette smoke (CS) for 30 days and 60 days. The COPD model was constructed, and their health hazards were compared and evaluated. CS from different tobacco varieties influenced rats in varying degrees at the tissue, cell and molecular levels. The rats in the "HHY" group showed obvious symptoms, such as cough and dyspnea, which were less severe in the "Zisu" and "Luole" groups. Pathological and morphological analyses, including scores, MLI, MAN, WAt/Pbm and WAm/Pbm, showed that "Zisu" and "Luole" caused less damage to the airways and lung parenchyma than "HHY". Significant increases in the numbers of total leukocytes and neutrophils in the BALF were found in "HHY" compared to those in "Zisu" and "Luole". Moreover, they caused less oxidative stress and apoptosis in lung tissues, as reflected by indicators such as ROS, MDA, T-AOC, GSH, the apoptotic index and the ratio of Bcl-2 to Bax. "Zisu" and "Luole" even altered the ratios of MMP-9/TIMP-1 and IFN-γ/IL-4 in lung tissues to a lesser degree. These differences between CS-exposed rats may be closely related to the altered expression of Nrf2, p38 MAPK and p-p38 MAPK. Changes in chemical composition via introducing genes from some medicinal plants may be an attractive strategy for tobacco harm reduction.

Threonine dehydrogenase regulates neutrophil homeostasis but not H3K4me3 levels in zebrafish.

l-threonine dehydrogenase (Tdh) is an enzyme that links threonine metabolism to epigenetic modifications and mitochondria biogenesis. In vitro studies show that it is critical for the regulation of trimethylation of histone H3 lysine 4 (H3K4me3) levels and cell fate determination of mouse embryonic stem cells (mESCs). However, whether Tdh regulates a developmental process in vivo and, if it does, whether it also primarily regulates H3K4me3 levels in this process as it does in mESCs, remains elusive. Here, we revealed that, in zebrafish hematopoiesis, tdh is preferentially expressed in neutrophils. Knockout of tdh causes a decrease in neutrophil number and slightly suppresses their acute injury-induced migration, but, unlike the mESCs, the level of H3K4me3 is not evidently reduced in neutrophils sorted from the kidney marrow of adult tdh-null zebrafish. These phenotypes are dependent on the enzymatic activity of Tdh. Importantly, a soluble supplement of nutrients that are able to fuel the acetyl-CoA pool, such as pyruvate, glucose and branched-chain amino acids, is sufficient to rescue the reduction in neutrophils caused by tdh deletion. In summary, our study presents evidence for the functional requirement of Tdh-mediated threonine metabolism in a developmental process in vivo. It also provides an animal model for investigating the nutritional regulation of myelopoiesis and immune response, as well as a useful tool for high-throughput drug/nutrition screening.

Progesterone amplifies allergic inflammation and airway pathology in association with higher lung ILC2 responses.

Perimenstrual worsening of asthma occurs in up to 40% of women with asthma, leading to increased acute exacerbations requiring clinical care. The role of sex hormones during these times remains unclear. In the current study, we used a translational approach to determine whether progesterone exacerbates allergic inflammation in the traditional chicken egg ovalbumin (OVA) model in BALB/c mice. Simultaneously, we used peripheral blood mononuclear cells (PBMC) from healthy human donors to assess the effects of progesterone on circulating group 2 innate lymphoid cells (ILC2). Briefly, lungs of ovariectomized (OVX) or sham-operated female (F-Sham) controls were implanted with a progesterone (P4, 25 mg) (OVX-P4) or placebo pellet (OVX-Placebo), followed by sensitization and challenge with ovalbumin (OVA). Progesterone increased total inflammatory histologic scores, increased hyper-responsiveness to methacholine (MCh), increased select chemokines in the bronchoalveolar lavage (BAL) and serum, and increased ILC2 and neutrophil numbers, along the airways compared with F-Sham-OVA and OVX-Placebo-OVA animals. Lung ILC2 were sorted from F-Sham-OVA, OVX-Placebo-OVA and OVX-P4-OVA treated animals and stimulated with IL-33. OVX-P4-OVA lung ILC2 were more responsive to interleukin 33 (IL-33) compared with F-Sham-OVA treated, producing more IL-13 and chemokines following IL-33 stimulation. We confirmed the expression of the progesterone receptor (PR) on human ILC2, and showed that P4 + IL-33 stimulation also increased IL-13 and chemokine production from human ILC2. We establish that murine ILC2 are capable of responding to P4 and thereby contribute to allergic inflammation in the lung. We confirmed that human ILC2 are also hyper-responsive to P4 and IL-33 and likely contribute to airway exacerbations following allergen exposures in asthmatic women with increased symptoms around the time of menstruation.NEW & NOTEWORTHY There is a strong association between female biological sex and severe asthma. We investigated the allergic immune response, lung pathology, and airway mechanics in the well-described chicken egg ovalbumin (OVA) model with steady levels of progesterone delivered throughout the treatment period. We found that progesterone enhances the activation of mouse group 2 innate lymphoid cells (ILC2). Human ILC2 are also hyper-responsive to progesterone and interleukin 33 (IL-33), and likely contribute to airway exacerbations following allergen exposures in women with asthma.

Choroid plexus immune cell response in murine hydrocephalus induced by intraventricular hemorrhage

BackgroundIntraventricular hemorrhage (IVH) and associated hydrocephalus are significant complications of intracerebral and subarachnoid hemorrhage. Despite proximity to IVH, the immune cell response at the choroid plexus (ChP) has been relatively understudied. This study employs CX3CR-1GFP mice, which marks multiple immune cell populations, and immunohistochemistry to outline that response.MethodsThis study had four parts all examining male adult CX3CR-1GFP mice. Part 1 examined naïve mice. In part 2, mice received an injection 30 µl of autologous blood into right ventricle and were euthanized at 24 h. In part 3, mice underwent intraventricular injection of saline, iron or peroxiredoxin 2 (Prx-2) and were euthanized at 24 h. In part 4, mice received intraventricular iron injection and were treated with either control or clodronate liposomes and were euthanized at 24 h. All mice underwent magnetic resonance imaging to quantify ventricular volume. The ChP immune cell response was examined by combining analysis of GFP(+) immune cells and immunofluorescence staining.ResultsIVH and intraventricular iron or Prx-2 injection in CX3CR-1GFP mice all induced ventriculomegaly and activation of ChP immune cells. There were very marked increases in the numbers of ChP epiplexus macrophages, T lymphocytes and neutrophils. Co-injection of clodronate liposomes with iron reduced the ventriculomegaly which was associated with fewer epiplexus and stromal macrophages but not reduced T lymphocytes and neutrophils.ConclusionThere is a marked immune cell response at the ChP in IVH involving epiplexus cells, T lymphocytes and neutrophils. The blood components iron and Prx-2 may play a role in eliciting that response. Reduction of ChP macrophages with clodronate liposomes reduced iron-induced ventriculomegaly suggesting that ChP macrophages may be a promising therapeutic target for managing IVH-induced hydrocephalus.

Blood Count and Renal Functionality Assessments in the Emergency Section Disclose Morbidity and Mortality in Omicron COVID-19 Patients: A Retrospective Study.

Background: SARS-CoV-2 is the coronavirus responsible for the COVID-19 pandemic. Even though we are no longer in a pandemic situation, people are still getting infected, some of them need hospitalization and a few of them die. Methods: We conducted a retrospective study including 445 patients who accessed the Emergency Section of Policlinico Umberto I, Rome, Italy, where they had routine blood exams. In this study, we focused on the complete blood count, serum creatinine and azotemia. The data were analyzed using ANOVA, Spearman correlation and ROC analyses. They were divided into four groups based on their clinical outcomes: (1) the emergency group (patients who had mild forms and were quickly discharged); (2) the hospital ward group (patients who were admitted to the emergency section and were then hospitalized in a COVID-19 ward); (3) the intensive care unit (ICU) group (patients who required intensive assistance after the admission in the emergency section); (4) the deceased group (patients who had a fatal outcome after admission to the emergency section). Results: We found significant changes for creatinine, azotemia, hematocrit, mean corpuscular hemoglobin concentration, basophils, monocytes, red blood cell distribution width, hemoglobin, hematocrit and red blood cell numbers using ANOVA according to their clinical outcomes, particularly for the deceased group. Also, we found linear correlations of clinical outcomes with eosinophils, hemoglobin, hematocrit, mean corpuscular hemoglobin concentration, lymphocyte, neutrophil, platelet and red blood cell number and red blood cell distribution width. Conclusions: This study discloses an early association between "classical" routine blood biomarkers and the severity of clinical outcomes in Omicron patients.