Immature Neutrophils Research Articles

The role of transforming growth factor β in COVID-19 lung injury: clinical and diagnostic parallels

BACKGROUND: Severe acute respiratory syndrome causes complex immune responses of hyperactivation of immunocompetent cells, including increased degranulation activity of mast cells and release of their secretome products. Mast cell granules may contain a lot of profibrotic enzymes and cytokines (chymase, tryptase, interleukin-4, 10, and 13) as well as growth factors. The entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into the body and the subsequent strong immune and inflammatory response and dysregulation of coagulation and fibrinolytic pathways cause massive activation of latent (inactive) transforming growth factor β (TGF-β) in the lungs and the latent pool of TGF-β in the blood of patients with coronavirus disease 2019 (COVID-19). AIM: To evaluate the role of TGF-β in lung involvement in patients with COVID-19 by examining autopsy lung material, determining the quantitative level of TGF-β with further correlation analysis of clinical and laboratory parameters. MATERIALS AND METHODs: The study included autopsy lung samples from patients who died from severe COVID-19. Autopsies were performed 2 days after the patients died. Autopsy material was collected for histology. Correlation analysis was performed between the number of TGF-β-positive cells and clinical and laboratory parameters. RESULTS: Extensive representation of TGF-β positive cells was found in autopsy tissues. A negative correlation was found between the number of TGF-β-positive cells and the blood concentration of band neutrophils (r=−0.617; p=0.033); between the number of TGF-β-positive cells and the concentration of C-reactive protein according to blood chemistry (r=–0.491; p=0.013). A positive correlation was found between the number of TGF-β-positive cells and blood platelet concentration (r=0.384; p=0.012); the number of TGF-β-positive cells and erythrocyte sedimentation rate (r=0.409; p=0.025). A positive correlation was also found between the number of TGF-β-positive cells and the presence of a cough in the patient at the beginning of the hospital stay (r=0.367; p=0.046). CONCLUSION: A correlation was found between the number of TGF-β-positive cells, neutrophil concentration, platelet concentration, erythrocyte sedimentation rate, C-reactive protein concentration, and the presence of cough in patients who died from severe COVID-19. These correlations suggest the negative role of TGF-β and the therapeutic possibilities of regulating its activation. Further studies in a larger number of patients are required.

Abstract C019: IL27R signaling regulates neutrophils maturation, activation and function in colorectal cancer-liver metastases

Abstract Colorectal cancer (CRC) is the third most common cancer and fourth cause of cancer death worldwide. The liver is the most common organ for CRC metastasis, which is a major cause of death for CRC patients. Therefore, a better understanding of mechanisms facilitating CRC liver metastasis is in urgent need. IL27 is a member of IL6/IL12 cytokines superfamily which have a critical role in tumor microenvironment to affect tumorigenesis and metastasis. IL27 is secreted by activated macrophages and dendritic cells, and IL27R is expressed in various immune cells, mediating IL27-dependent pro-inflammatory or anti-inflammatory immune responses. However, the role of myeloid IL27 signaling in CRC-liver metastasis remains unclear. To study the role of IL27R signaling in myeloid cells, we generated Il27ra fl/fl mice and crossed them with LysM cre deleter to obtain LysM cre+ Il27ra f/f mice. Using MC-38 CRC cells portal vein injection model, we found that myeloid IL27Ra deletion leads to increased CRC-liver metastasis accompanied by increase in neutrophils, particularly Ly6G+Cxcr2-CD101- immature neutrophils, in circulation as well as tumors in LysM cre+ Il27ra f/f mice. Single-cell sequencing of tumor-infiltrating immune cells revealed that lack of IL27Ra in myeloid cells promoted neutrophil recruitment and degranulation as well as reactive oxygen species (ROS) and reactive nitrogen species (RNS) production but inhibited neutrophil maturation and production of pro-inflammatory chemokines and cytokines such as CXCL10, CSF1 and TNF. Furthermore, IL27Ra deficient neutrophils displayed heightened inflammatory response when stimulated with LPS in vitro. Collectively, our work reveals novel role of myeloid IL27Ra signaling that inhibits metastatic liver colonization by promoting neutrophil maturation, restricting neutrophil infiltration and degranulation. Citation Format: Jiani Zhu, Zhengzheng Shi, Ekaterina Koltsova. IL27R signaling regulates neutrophils maturation, activation and function in colorectal cancer-liver metastases [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C019.

Abstract PR010: DICER1 cancer predisposition tumor promotion mediated non-cell autonomously via neutrophils and NETosis

Abstract DICER1 cancer predisposition syndrome is a heritable condition where affected patients have increased risk of neoplasms including fusion-negative rhabdomyosarcoma (FN-RMS). The syndrome is defined by germline heterozygous loss of function mutations in DICER1, but it remains unclear exactly how these mutations predispose children to cancer. To gain insight into the role of Dicer1 loss in DICER1 cancer predisposition, we deleted the Dicer1 gene both in the germline or conditionally within the tumor cell in our previously established mouse model of FN-RMS. One would expect the germline loss of one allele to provide a sensitized background in the tumor cell to acquire a second hit mutation. However, we observed faster tumor onset and increased penetrance in mice with germline heterozygous Dicer1 loss (Dicer1 +/- ) but not in mice when Dicer1 loss was restricted to the tumor cells (Dicer1 Flox/+ ), demonstrating that haploinsufficient tumor suppressor activity of Dicer1 loss requires non-cell autonomous cell types. Single cell RNA sequencing (scRNA-Seq) revealed significant expansion of immature neutrophils in Dicer1 +/- tumors, which were enriched for proteases associated with neutrophil extracellular traps (NETs). NETs are webs of chromatin and proteases released when neutrophils in response to inflammatory stimuli in process termed NETosis. We show Dicer1 +/- murine and human tumors are enriched for neutrophils and tumor-bearing mice had abundant circulating NETs. NETs cause significant damage to the local extracellular matrix (ECM) and have been implicated in tumor promotion. In addition, neutrophil enrichment, we found that Dicer1 +/- tumors show significant ECM remodeling and are increased C5a, a potent neutrophil chemoattractant and NET-priming factor. These results suggest NETosis is upregulated in Dicer1 +/- FN-RMS tumors. Ligand-receptor pair analysis (iTALK) on the scRNA- Seq data revealed a putative interaction between a NET-derived ligand and EGFR and IGF1R on tumor cells, suggesting direct tumor promoting signaling from NET-to-tumor. We validated this novel FN-RMS promotion mechanism in vitro using human FN-RMS cell lines and observed that this NET-derived ligand promoted FN-RMS growth through both EGFR and IGF1R signaling. NET release requires citrullination of histone H3 mediated by peptidyl arginine deiminase 4 (PADI4) to facilitate decondensation of chromatin. We intercrossed the Padi4 -/- allele into our tumor model to genetically block NETosis and observed complete rescue of the accelerated tumor onset and increased penetrance observed in Dicer1 +/- mice. These results demonstrate that NETosis promotes the growth of Dicer1 +/- FN-RMS tumors and is required for Dicer1 +/- haploinsufficiency. These findings may be applicable to many DICER1 syndrome- associated cancers, as neutrophils which get converted to tumor promoters by heterozygous DICER1 loss are present in DICER1 syndrome patients regardless of tumor type and suggest targeting neutrophils/NET-release may reduce cancer risk in DICER1 +/- individuals. Citation Format: Randolph K Larsen, Jason A Hanna, Hongjian Jin, Kristen B Reed, Darden W Kimbrough, Kyna Voung, Myron K Evans, Casey G Langdon, Catherine J Drummond, Matthew R Garcia, David Finkelstein, Patrick A Schreiner, Jerold E Rehg, Kris Ann P Schultz, Mark E Hatley. DICER1 cancer predisposition tumor promotion mediated non-cell autonomously via neutrophils and NETosis [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: RNAs as Drivers, Targets, and Therapeutics in Cancer; 2024 Nov 14-17; Bellevue, Washington. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(11_Suppl):Abstract nr PR010.

Supression of shielding effect of large area field emitter cathode in radio frequency gun environment

Abstract Utilisation of large area field emitters (LAFE) cathodes for rf gun injector hold promise for delivering compact, high power and high brightness electron beam for advanced accelerator technologies. LAFEs subjected to DC electric fields posses significant challenges due to the shielding effect which restricts emission from central emitters and decreases the overall current density. Mitigating the shielding effect of LAFE in rf gun environment is essential for meeting the desired beam quality requirement in an accelerator. The current distribution of LAFE under DC conditions depend on its various geometrical parameters such as emitter height, inter-emitter distance, aspect ratio, number of emitters. Additionally, in rf gunsetup, LAFEs are subjected to variable macroscopic electric field at different emitter position which can potentially alter the current distribution compared to DC fields. In this work, we have systematically studied the shielding effect properties of LAFE in rf gun environment under the influence of various LAFE parameters. A semi-analytical approachhas been adopted to estimate the current distribution which combines the analytically calculated field enhancement factor (γ) and numerically calculated applied rf field values. This new methodology was first validated using COMSOL simulation and then employed for field emission performance estimation of a LAFE cathode integrated in a½ cell S-band (2856 MHz) rf gun. The simulation results reveals that under favourable conditions, a Gaussian spatial distribution of beam can be obtained from LAFE thus countering the shielding effect typical in DC fields. By optimizing the LAFE parameters, the desired current and beam distribution pattern can be achieved. This study highlights the adoption of a promising approach for designing LAFE cathodes suitable for rf gun which can lead to advancement of field emission technologies for accelerator-related applications.

Virulence-linked adhesin drives mutualist colonization of the bee gut via biofilm formation.

Bacterial biofilms are stable multicellular structures that can enable long term host association. Yet, the role of biofilms in supporting gut mutualism is still not fully understood. Here, we investigate Snodgrassella alvi, a beneficial bacterial symbiont of honey bees, and find that biofilm formation is required for its colonization of the bee gut. We constructed fifteen S. alvi mutants containing knockouts of genes known to promote colonization with putative roles in biofilm formation. Genes required for colonization included staA and staB, encoding trimeric autotransporter adhesins (TAAs) and mltA, encoding a lytic transglycosylase. Intriguingly, TAAs are considered virulence factors in pathogens but support mutualism by the symbiont S. alvi. In vitro, biofilm formation was reduced in ΔstaB cells and abolished in the other two mutants. Loss of staA also reduced auto-aggregation and cell-cell connections. Based on structural predictions, StaA/B are massive (>300 nm) TAAs with many repeats in their stalk regions. Further, we find that StaA/B are conserved across Snodgrassella species, suggesting that StaA/B-dependent colonization is characteristic of this symbiont lineage. Finally, staA deletion increases sensitivity to bactericidal antimicrobials, suggesting that the biofilm indirectly buffers against antibiotic stress. In all, the inability of two biofilm-deficient strains (ΔstaA and ΔmltA) to effectively mono-colonize bees indicates that S. alvi biofilm formation is required for colonization of the bee gut. We envision the bee gut system as a genetically tractable model for studying the physical basis of biofilm-mutualist-gut interactions.

6897 The Role of Neutrophil Heterogeneity on T-cell Immunity in Advanced Thyroid Cancer Patients

Abstract Disclosure: Y. Kang: None. S. Lee: None. J. Yoon: None. D. Kang: None. J. Lee: None. Neutrophil heterogeneity is involved in autoimmune diseases, sepsis, and several cancers. However, the link between neutrophil heterogeneity and T-cell immunity in thyroid cancer is incompletely understood. We investigated the circulating neutrophil heterogeneity in 3 undifferentiated thyroid cancer (UTC), 14 differentiated thyroid cancer (DTC) (4 Stage IV, 10 Stage I-II), and healthy controls (n=10) by transcriptomic data and cytometry. Participants with UTC had a significantly higher proportion of immature high-density neutrophils (HDN) and lower proportion of mature HDN in peripheral blood compared to DTC. The proportion of circulating PD-L1+ immature neutrophils were significantly increased in advanced cancer patients. Unsupervised analysis of transcriptomics data from circulating HDN revealed downregulation of innate immune response and T cell receptor signaling pathway in cancer patients. Moreover, UTC patients revealed the upregulation of glycolytic process and glutamate receptor signaling pathway. Comparative analysis across tumor types and stages revealed the downregulation of various T cell related pathways, such as T cell receptor signaling pathway and T cell proliferation in advanced cancer patients. Moreover, the proportions of CD8+ and CD4+ T effector memory CD45RA+ (TEMRA) cells from peripheral blood were significantly decreased in UTC patients compared to DTC patients. Finally, we demonstrated that proportions of tumor infiltrated neutrophils were increased and related with poor prognosis in advanced thyroid cancer using data from our RNA-seq and TCGA (The Cancer Genome Atlas) data. In conclusion, observed prevalence of circulating immature high-density neutrophils and their immunosuppressive features in undifferentiated thyroid cancers underscore the importance of understanding neutrophil dynamics in the context of tumor progression in thyroid cancer. Presentation: 6/3/2024

Fatty acid metabolism in neutrophils promotes lung damage and bacterial replication during tuberculosis.

Mycobacterium tuberculosis (Mtb) infection induces a marked influx of neutrophils into the lungs, which intensifies the severity of tuberculosis (TB). The metabolic state of neutrophils significantly influences their functional response during inflammation and interaction with bacterial pathogens. However, the effect of Mtb infection on neutrophil metabolism and its consequent role in TB pathogenesis remain unclear. In this study, we examined the contribution of glycolysis and fatty acid metabolism on neutrophil responses to Mtb HN878 infection using ex-vivo assays and murine infection models. We discover that blocking glycolysis aggravates TB pathology, whereas inhibiting fatty acid oxidation (FAO) yields protective outcomes, including reduced weight loss, immunopathology, and bacterial burden in lung. Intriguingly, FAO inhibition preferentially disrupts the recruitment of a pathogen-permissive immature neutrophil population (Ly6Glo/dim), known to accumulate during TB. Targeting carnitine palmitoyl transferase 1a (Cpt1a)-a crucial enzyme in mitochondrial β-oxidation-either through chemical or genetic methods impairs neutrophils' ability to migrate to infection sites while also enhancing their antimicrobial function. Our findings illuminate the critical influence of neutrophil immunometabolism in TB pathogenesis, suggesting that manipulating fatty acid metabolism presents a novel avenue for host-directed TB therapies by modulating neutrophil functions.

Neutrophil Diversity (Immature, Aged, and Low-Density Neutrophils) and Functional Plasticity: Possible Impacts of Iron Overload in β-Thalassemia.

Neutrophil dysfunction is a form of immune suppression in patients with β-thalassemia (Beta-thal), although data on this are limited. In this study, blood from patients and healthy volunteers was analyzed. Flow cytometry analysis demonstrated an increase in immature neutrophils (CD16- CD62L+) and aged (senescent) neutrophils (CD16+ CD62L-) in Beta-thal patients compared to healthy volunteers. The Beta-thal neutrophils demonstrated less prominent chemotaxis and phagocytosis than healthy neutrophils at the baseline. With phorbol myristate acetate (PMA) or lipopolysaccharide (LPS) stimulations, some of the indicators, including the flow cytometry markers (CD11b, CD62L, CD66b, CD63, apoptosis, and reactive oxygen species) and neutrophil extracellular traps (NETs; detected by anti-citrullinated histone 3 immunofluorescence), were lower than the control. Additionally, low-density neutrophils (LDNs), which are found in the peripheral blood mononuclear cell (PBMC) fraction, were observed in Beta-thal patients but not in the control group. The expression of CD11b, CD66b, CD63, arginase I, and ROS in LDNs was higher than the regular normal-density neutrophils (NDNs). The proliferation rate of CD3+ T cells isolated from the PBMC fraction of healthy volunteers was higher than that of the cells from patients with Beta-thal. The incubation of red blood cell (RBC) lysate plus ferric ions with healthy NDNs transformed the NDNs into the aged neutrophils (decreased CD62L) and LDNs. In conclusion, iron overload induces neutrophil diversity along with some dysfunctions.

Deferasirox, an iron chelator, impacts myeloid differentiation by modulating NF-kB activity via mitochondrial ROS.

The iron chelator deferasirox (DFX) is effective in the treatment of iron overload. In certain patients with myelodysplastic syndrome, DFX can also provide a dramatic therapeutic benefit, improving red blood cell production and decreasing transfusion requirements. Nuclear Factor-kappa B (NF-kB) signalling has been implicated as a potential mechanism behind this phenomenon, with studies focusing on the effect of DFX on haematopoietic progenitors. Here, we examine the phenotypic and transcriptional effects of DFX throughout myeloid cell maturation in both murine and human model systems. The effect of DFX depends on the stage of differentiation, with effects on mitochondrial reactive oxygen species (ROS) production and NF-kB pathway regulation that vary between progenitors and neutrophils. DFX triggers a greater increase in mitochondrial ROS production in neutrophils and this phenomenon is mitigated when cells are cultured in hypoxic conditions. Single-cell transcriptomic profiling revealed that DFX decreases the expression of NF-kB and MYC (c-Myc) targets in progenitors and decreases the expression of PU.1 (SPI1) gene targets in neutrophils. Together, these data suggest a role of DFX in impairing terminal maturation of band neutrophils.

KC-like chemokine as a biomarker of sepsis in dogs with pyometra

BackgroundSepsis, defined as a dysregulated inflammatory response to infection inducing organ dysfunction, is a common cause of mortality in both humans and animals. Early detection and treatment is essential for survival, but accurate diagnosis is challenging due to the lack of specific biomarkers for sepsis. This study explored the potential of the keratinocyte-derived chemokine (KC)-like protein in dogs as a biomarker of sepsis in dogs with bacterial uterine infection (pyometra). The aim was to compare KC-like concentrations in dogs with pyometra with or without sepsis and to assess associations between KC-like and clinical variables, including days of hospitalization as an outcome.ResultsA mouse KC ELISA was validated and used to determine the concentrations of KC-like in serum from 34 dogs with pyometra and 18 healthy controls. Dogs with pyometra were classified as having sepsis based on two different criteria for systemic inflammatory response syndrome (SIRS), resulting in 74% and 30% sepsis-positive, respectively. The concentration of KC-like protein was higher in pyometra dogs with sepsis than in pyometra dogs without sepsis (p < 0.05) and in healthy controls (p < 0.0001) when using either of the two SIRS criteria. Moreover, KC-like was slightly increased in dogs with pyometra without sepsis compared with healthy controls when using the more stringent SIRS criteria (p < 0.05). Analyses of all dogs showed that KC-like concentrations correlated positively with hospitalization days, C-reactive protein (CRP) concentrations, white blood cells, and percentage of band neutrophils; however, KC-like correlated negatively with hemoglobin and did not correlate with circulating creatinine.ConclusionsOur results suggest that circulating KC-like protein increases in dogs with sepsis in pyometra and that KC-like is associated with more severe clinical illness. These findings support a potential role of KC-like as a biomarker of sepsis; however, the true identity of KC-like in dogs has yet to be uncovered.

Hematological and biochemical profiles, infection and habitat quality in an urban rat population.

Host condition is key in understanding disease dynamics. In an urban population of Rattus norvegicus, we aimed to assess whether infection of Leptospira interrogans and helminths was associated with patterns of host hematological and hormone-biochemical stress-related conditions. Rat kidney imprints and urine were used to identify and quantify L. interrogans, and feces samples for helminth eggs and corticosterone metabolites. Blood samples were taken for complete blood counts and specific biochemicals in rats' sera. Principal Component Analyses were performed to check whether rats would be grouped according to health profiles. We obtained hematological and hormone-biochemical data from 95 and 61 rats, respectively. Hematological PCA revealed distinct rat groups: typical (T), eosinophil deficient (Eos-D), eosinophil- and monocyte- deficient (EM-D) and monocyte deficient with high immature neutrophils (Mon-D). No association between L. interrogans or helminths and rat health profiles was observed, except with Trichiuridae, which mean intensity was significantly higher when all deficient groups were pooled together compared to the T-group. The poorest condition group was found in areas with fewer rat burrows than the T-group, indicating EM-D had a reduced ability to occupy "good" quality habitats. In natural populations, hematological profiles may reflect host's overall condition, instead of responses to specific infections.

Emergence of dysfunctional neutrophils with a defect in arginase-1 release in severe COVID-19.

Neutrophilia occurs in patients infected with SARS-CoV-2 (COVID-19) and is predictive of poor outcomes. Here, we link heterogenous neutrophil populations to disease severity in COVID-19. We identified neutrophils with features of cellular aging and immunosuppressive capacity in mild COVID-19 and features of neutrophil immaturity and activation in severe disease. The low-density neutrophil (LDN) number in circulating blood correlated with COVID-19 severity. Many of the divergent neutrophil phenotypes in COVID-19 were overrepresented in the LDN fraction and were less detectable in normal-density neutrophils. Functionally, neutrophils from patients with severe COVID-19 displayed defects in neutrophil extracellular trap formation and reactive oxygen species production. Soluble factors secreted by neutrophils from these patients inhibited T cell proliferation. Neutrophils from patients with severe COVID-19 had increased expression of arginase-1 protein, a feature that was retained in convalescent patients. Despite this increase in intracellular expression, there was a reduction in arginase-1 release by neutrophils into serum and culture supernatants. Furthermore, neutrophil-mediated T cell suppression was independent of arginase-1. Our results indicate the presence of dysfunctional, activated, and immature neutrophils in severe COVID-19.

Genomic insight into COVID-19 severity in MAFLD patients: a single-center prospective cohort study.

This study investigated the influence of single nucleotide polymorphisms (SNPs) in genes associated with the interferon pathway (IFNAR2 rs2236757), antiviral response (OAS1 rs10774671, OAS3 rs10735079), and viral entry (ACE2 rs2074192) on COVID-19 severity and their association with nonalcoholic fatty liver disease (MAFLD). We did not observe a significant association between the investigated SNPs and COVID-19 severity. While the IFNAR2 rs2236757 A allele was correlated with higher creatinine levels upon admission and the G allele was correlated with lower band neutrophils upon discharge, these findings require further investigation. The distribution of OAS gene polymorphisms (rs10774671 and rs10735079) did not differ between MAFLD patients and non-MAFLD patients. Our study population's distribution of ACE2 rs2074192 genotypes and alleles differed from that of the European reference population. Overall, our findings suggest that these specific SNPs may not be major contributors to COVID-19 severity in our patient population, highlighting the potential role of other genetic factors and environmental influences.

Cholangiocarcinoma: Consistent clinical, cytological, hematological, and biochemical findings and pathomorphology of the liver and kidney in five exotic dog breeds in Abeokuta, Nigeria.

Cholangiocarcinomas are malignant neoplasms that originate from any part of the bile duct epithelium. It is one of the most common liver tumors in dogs. This study described the clinical, cytological, hematological, biochemical, and pathomorphological findings of five cholangiocarcinoma cases in exotic breed dogs aged 2-5 years to aid in clinical diagnosis. This study used dogs presented at different times from 2012 to 2021 at the Veterinary Teaching Hospital, Federal University of Agriculture, Abeokuta. History, clinical signs, and vital parameters were recorded. Blood samples were collected for hematology and serum chemistry. Abdominocentesis was performed for cytological diagnosis. All dogs died during treatment, and postmortem examinations were performed. At postmortem, fine needle aspirates were collected from the liver and mesenteric lymph nodes and liver and kidney samples were fixed in 10% neutral-buffered formalin. The dogs showed signs of severe malnutrition, jaundice, and bloating. The hematological analysis indicated anemia, neutrophilia without band neutrophils, and lymphopenia, indicative of a stress hemogram. The serum biochemistry test revealed lower levels of total proteins, albumin, and globulin and higher levels of serum enzymes. Abdominal fluid and mesenteric lymph node cytology revealed clusters of epithelial neoplastic cells. A postmortem examination revealed the liver's nodular enlargement with the presence of button-like ulcers. Neoplastic epithelial cells are solid masses with hyperchromatic nuclei surrounded by fibrous connective tissues. Cholangiocarcinoma, diagnosed over a period of time in five exotic breeds of dog, consistently presents with the same clinical and postmortem findings, aiding in clinical diagnosis. However, the diagnosis of the disease is not possible in the early stage because of the absence of specific clinical signs. In dogs and possibly other animal species presenting with emaciation, lethargy, icterus, and distended abdomen, cholangiocarcinoma should be suspected, and cytological examination of the abdominal fluid and lymph node aspirates should be performed despite the absence of advanced equipment.

Abstract P184: Increased Granulopoiesis, Kidney Neutrophil Infiltration, and Renal Damage in a Mouse Model of Psoriasis

Psoriasis is an autoimmune skin disease marked by T cell-mediated hyperproliferation of epidermal keratinocytes. Most psoriasis-related morbidity and mortality stems from an elevated risk of renal and cardiovascular disease, but mechanisms remain unclear. Although neutrophils are not directly targeted with current psoriasis therapies, neutrophils are increased in the skin and circulation of these patients. We hypothesized that excess skin inflammation in psoriasis drives increased G-CSF-dependent granulopoiesis leading to renal neutrophil infiltration and dysfunction. Employing a KC-Tie2 mouse model of psoriasis with keratinocyte-specific overexpression of the angiopoietin receptor Tie2 (KC-Tie2), we observed 2-3-fold elevations in multiple indices of renal damage including urine albumin, urine NGAL, and glomerulosclerosis in KC-Tie2 mice compared to littermate controls (all P&lt;0.05). KC-Tie2 mice also demonstrated 13 mm Hg higher daytime systolic blood pressure compared to littermate controls (P&lt;0.05). Using flow cytometry, we found that KC-Tie2 mice had an increase not only in cutaneous neutrophils but also an approximate 10-fold increase in renal neutrophils (P&lt;0.001). KC-Tie2 kidneys also exhibited increased vital and suicidal neutrophil extracellular trap (NET) formation, representing a potential mechanism for the observed renal damage. Interestingly, the increase in renal neutrophils was selective relative to other major immune cell populations such as dendritic cells, lymphocytes, monocytes, and macrophages. Similar selective increases in neutrophils were noted in the circulation, aorta, and spleen. We thus examined neutrophil production in the bone marrow, and observed significant increases in immature Ly6g low and Ly6g intermediate neutrophils (P&lt;0.0001) as well as total Ly6g + neutrophils (P&lt;0.05), with no change in mature Ly6g high neutrophils in the bone marrow of KC-Tie2 mice. These findings are consistent with increased granulopoiesis, prompting an examination of the key mediator of granulopoiesis, granulocyte colony-stimulating factor (G-CSF). KC-Tie2 mice exhibited marked increases in G-CSF in both the skin and plasma (P&lt;.001 for both). In conclusion, our findings demonstrate increased renal damage in a mouse model of psoriasis, concomitant with increases in granulopoiesis and total and NETotic renal neutrophils, potentially unveiling a novel link between skin inflammation and renal damage via enhanced G-CSF-mediated granulopoiesis.

The FLARE Score and Circulating Neutrophils in Patients with Cancer and COVID-19 Disease.

Inflammation and neutrophils play a central role in both COVID-19 disease and cancer. We aimed to assess the impact of pre-existing tumor-related inflammation on COVID-19 outcomes in patients with cancer and to elucidate the role of circulating neutrophil subpopulations. We conducted a multicenter retrospective analysis of 524 patients with cancer and SARS-CoV-2 infection, assessing the relationship between clinical outcomes and circulating inflammatory biomarkers collected before and during COVID-19 infection. Additionally, a single-center prospective cohort study provided data for an exploratory analysis, assessing the immunophenotype of circulating neutrophils and inflammatory cytokines. The primary endpoints were 30-day mortality and the severity of COVID-19 disease. Prior to COVID-19, 25% of patients with cancer exhibited elevated dNLR, which increased to 55% at the time of COVID-19 diagnosis. We developed the FLARE score, incorporating both tumor- and infection-induced inflammation, which categorized patients into four prognostic groups. The poor prognostic group had a 30-day mortality rate of 68%, significantly higher than the 23% in the favorable group (p < 0.0001). This score proved to be an independent predictor of early mortality. This prospective analysis revealed a shift towards immature forms of neutrophils and higher IL-6 levels in patients with cancer and severe COVID-19 infection. A pre-existing tumor-induced pro-inflammatory state significantly impacts COVID-19 outcomes in patients with cancer. The FLARE score, derived from circulating inflammatory markers, emerges as an easy-to-use, globally accessible, effective tool for clinicians to identify patients with cancer at heightened risk of severe COVID-19 complications and early mortality who might benefit most from immediate and intensive treatment strategies. Furthermore, our findings underscore the significance of immature neutrophils in the progression of COVID-19 in patients with cancer, advocating for further investigation into how these cells contribute to both cancer and COVID-19 disease.

Periprosthetic joint infection in patients with rheumatoid arthritis: case series

Introduction The differential diagnosis of periprosthetic joint infection (PJI) is challenging in patients with systemic diseases due to identical clinical and laboratory patterns and activity of the inflammatory process.The objective was to evaluate the diagnostic data and results of debridement of PJI in patients with rheumatoid arthritis using a case series.Material and methods A retrospective analysis of surgical treatment of PJI was produced in patients with rheumatoid arthritis between 2014 and 2022. PJI was verified based on ICM criteria. A poor outcome included the presence of clinical and laboratory signs of infection on admission to the second stage of treatment and recurrence after successful debridement.Results Among the 524 cases of PJI, 35 (6.7 %) were patients with rheumatoid arthritis with 48.6 % receiving antibiotics prior to admission. Culture-negative infection was recorded in 38.4 %. PJI was not confirmed in five cases (14.3 %). High average values of inflammatory markers were registered in the blood (ESR, CRP and D-dimer) before and after debridement; decreased ESR and leukocyte count in the synovial fluid was statistically significant. Favorable outcomes were obtained in 82.9 % of cases at mid term with every fifth patient treated with a spacer or arthrodesis.Discussion The incidence of culture-negative infection in patients with systemic diseases was reported as much as 27–37 %. A systematic review of the literature showed that the percentage of band neutrophils in synovial fluid has a sensitivity of 95.2 % and a specificity of 85.0 %, with an optimal threshold of 78 % sufficient to verify infection. The poor outcomes we identified resulted from two- or three-stage surgical treatment. Other authors reported better outcomes with two-stage debridement.Conclusion Culture-negative infection was common in cases of PJI observed in patients with rheumatoid arthritis. Favorable outcomes were seen mostly with two-stage surgical treatment. Inflammatory markers ESR, CRP and D-dimer did not reach normal values during diagnosis and treatment of infection indicating the inapplicability of standard diagnostic criteria for PJI in patients with rheumatoid arthritis.

The assembly of neutrophil inflammasomes during COVID-19 is mediated by type I interferons.

The severity of COVID-19 is linked to excessive inflammation. Neutrophils represent a critical arm of the innate immune response and are major mediators of inflammation, but their role in COVID-19 pathophysiology remains poorly understood. We conducted transcriptomic profiling of neutrophils obtained from patients with mild and severe COVID-19, as well as from SARS-CoV-2 infected mice, in comparison to non-infected healthy controls. In addition, we investigated the inflammasome formation potential in neutrophils from patients and mice upon SARS-CoV-2 infection. Transcriptomic analysis of polymorphonuclear cells (PMNs), consisting mainly of mature neutrophils, revealed a striking type I interferon (IFN-I) gene signature in severe COVID-19 patients, contrasting with mild COVID-19 and healthy controls. Notably, low-density granulocytes (LDGs) from severe COVID-19 patients exhibited an immature neutrophil phenotype and lacked this IFN-I signature. Moreover, PMNs from severe COVID-19 patients showed heightened nigericin-induced caspase1 activation, but reduced responsiveness to exogenous inflammasome priming. Furthermore, IFN-I emerged as a priming stimulus for neutrophil inflammasomes. These findings suggest a potential role for neutrophil inflammasomes in driving inflammation during severe COVID-19. Altogether, these findings open promising avenues for targeted therapeutic interventions to mitigate the pathological processes associated with the disease.

Abstract Tu148: cGAS-STING pathway promotes granulopoiesis and neutrophil differentiation in acute ischemia

Contemporary evidence supports neutrophils' complex roles beyond being the simple and powerful destruction tools in MI. However, our understanding remains limited. We especially lack the knowledge of how cGAS-STING regulates neutrophil functions in acute ischemia. The cGAS-STING pathway senses cytosolic DNA to produce IFN and ISGs and is a pillar of innate immunity. Early evidence suggested neutrophils did not express cGAS. Taking advantage of the improved detecting method, we revisited this topic because this pathway can play an essential role in neutrophil function in MI. Using purified neutrophils from WT and knockout mice (as control), we detected cGAS, STING, and IRF3 in these cells. To determine if cGAS-STING regulates neutrophil function, we first generated MI model in cGAS -/- , STING -/- mice, and their WT littermates and performed flow cytometry and RNA-seq analyses. We uncovered that inhibiting cGAS-STING decreases neutrophil production in bone marrow (BM) after ischemia. Interestingly, cGAS- and STING-deficient neutrophils express significantly higher levels of primary granule molecules such as MPO, Prtn3, Elane, Cts- (s, g, b, l) but much lower levels of the secondary and tertiary granule components , including Mmp9, Mmp8, Olfm4, Cd177, Lyz2, and Lyz1. Neutrophils acquire granules sequentially during differentiation. Therefore, our data suggest inhibiting cGAS-STING leads to a stagnated neutrophil differentiation in the BM and mobilizes CD101 - immature neutrophils into the circulation and MI hearts. Consistently, cGAS- and STING-deficient neutrophils release less MMP8 and MMP9 into the ischemic area. Ischemia does not trigger the degranulation of primary granules, as indicated by the minimal changes of CD63. Our data further suggest that TF C/EBP𝜹 functions downstream of cGAS-STING to promote neutrophil differentiation. Adoptive transfer experiments suggest the neutrophil-specific function of cGAS-STING. In conclusion, we identify cGAS-STING as a novel mechanism promoting emergency granulopoiesis and neutrophil differentiation after MI and uncover its functional implications in ischemia-induced remodeling. Studies using Mrp8-Cre-mediated cGAS-STING deletion in granulocyte/macrophage progenitors are in progress.

Prevalence of co-infections with Ehrlichia spp. or Theileria spp. in dogs naturally infected with babesiosis in the Eastern Cape province

BackgroundCanine babesiosis and ehrlichiosis are tick-borne infections of great significance in South Africa. Theileriosis in dogs in South Africa is still poorly understood. Co-infection with multiple tick-borne diseases has been documented and is perceived as a common occurrence in South Africa. ObjectivesThe main objective of this study was to determine the prevalence of co-infections with Ehrlichia canis or Theileria equi in dogs with babesiosis in the Eastern Cape province. There is a lack of data on canine tick-borne disease distribution in this region. Possible associations of population characteristics and haematological and biochemistry measures with a co-infection of E. canis or T. equi in these dogs were also investigated. MethodThe study population included 150 dogs naturally infected with babesiosis that presented to the Mdantsane State Veterinary Clinic between January 2021 and November 2021. Quantitative polymerase chain reaction was used to confirm the Babesia spp. that the dogs were infected with and to identify co-infections. Association with co-infection for the following parameters were evaluated: sex, breed, age, duration of illness, leukocyte count, band neutrophil count, monocyte count, platelet count, ARC, and serum globulin concentration. Positive and negative predictive values of monocytosis, leukopenia, band neutrophilia, thrombocytopenia, and non-regenerative absolute reticulocyte count for co-infection were also calculated. ResultsBabesia rossi was identified in 149/150 samples and B. vogeli in only 1/150 samples. A co-infection prevalence of 2.0% (3/149; 95% CI: 0.4–5.7) with B. rossi and E. canis was found. No other co-infections were reported. No investigated variables showed significant associations with co-infections. Monocytosis, in particular, was not associated with co-infection. ConclusionCo-infection with other tick-borne diseases in dogs with babesiosis is uncommon in the Eastern Cape province. These findings raise the possibility that B. rossi may have a protective effect against other tick-borne diseases.