Impaired formation of neutrophil extracellular traps in patients with MDS

A network pharmacology and transcriptome analysis of the therapeutic effects of tea tree oil on the lungs of chicks exposed to hydrogen sulfide

This study investigated the use of tea tree oil (TTO) in the treatment of H2S-induced lung injury in chickens, focusing on the detoxification mechanism. H2S can damage the respiratory system and reduce growth performance. TTO can improve immune inflammation and growth performance. The mechanism by which TTO mitigates the harmful effects of H2S on chicken lungs remains unclear. Therefore, the experimental model was established by H2S exposure and TTO addition in drinking water. The 240 one-day-old Roman pink chicks were selected for the experiment. The trial was divided into control group (CON), treatment group (TTG, 0.02 mL/L TTO+H2S) and H2S exposure group (AVG, H2S). There were 4 replicates in each group and the trial lasted for 42 d. The therapeutic effect of TTO on lung injury in chickens were determined by growth performance evaluation, transcription sequencing and network pharmacology analysis. The results showed that in the test's third week, the body weights of the chickens in the CON were higher than those in the AVG and TTG (P < 0.05). Pathological sections showed that TTO alleviated the symptoms of lung inflammation and bleeding caused by ROS. As showed by transcriptional sequencing, the mRNA expression of apoptosis-related genes Caspase-9, BAK-1, BCL-2 and BAX were significantly altered (P < 0.05). Meanwhile, the mRNA expression of inflammation-related genes IL-2, IL-6, and IL-17 were downregulated (P < 0.05). Network pharmacological analysis showed that CA2, CA4, GABRA5 and ADH1C were the key targets of TTO. The TTO treatment significantly altered these targets (P < 0.05). Molecular docking confirmed the strong binding ability between the active component and the targets. This study showed that TTO inhibits H2S-induced oxidative damage to the lungs, thereby improving their health status. This provides a new solution for the prevention of harmful gas in the poultry industry.

Deficiency of hasB accelerated the clearance of Streptococcus equi subsp. Zooepidemicus through gasdermin d-dependent neutrophil extracellular traps

Streptococcus equi subsp. zooepidemicus (S. zooepidemicus, SEZ) is an essential zoonotic bacterial pathogen that can cause various inflammation, such as meningitis, endocarditis, and pneumonia. UDP-glucose dehydrogenase (hasB) is indispensable in synthesizing SEZ virulence factor hyaluronan capsules. Our study investigated the infection of hasB on mice response to SEZ by employing a constructed capsule-deficient mutant strain designated as the ΔhasB strain. This deficiency was associated with a reduced SEZ bacterial load in the mice's blood and peritoneal lavage fluid (PLF) post-infection. Besides, the ΔhasB SEZ strain exhibited a higher propensity for neutrophil infiltration and release of cell-free DNA (cfDNA) in vivo compared to the wild-type (WT) SEZ strain. In vitro experiments further revealed that ΔhasB SEZ more effectively induced the formation of neutrophil extracellular traps (NETs) containing histone 3 (H3), neutrophil elastase (NE), and DNA, than its WT counterpart. Moreover, the release of NETs was determined to be gasdermin D (GSDMD)-dependent during the infection process. Taken together, these findings underscore that the deficiency of the hasB gene in SEZ leads to enhanced GSDMD-dependent NET release from neutrophils, thereby reducing SEZ's capacity to resist NETs-mediated eradication during infection. Our finding paves the way for the development of innovative therapeutic strategies against SEZ.

Liraglutide enhances the effect of checkpoint blockade in lung and liver cancers through the inhibition of neutrophil extracellular traps

Glucagon-like peptide-1 (GLP-1) regulates glycemic excursions by augmenting insulin production and inhibiting glucagon secretion. Liraglutide, a long-acting GLP-1 analog, can improve glycemic control for treating type 2 diabetes and prevent neutrophil extravasation in inflammation. Here, we explored the role of liraglutide in the development and therapy of murine lung and liver cancers. In this study, liraglutide substantially decreased circulating neutrophil extracellular trap (NET) markers myeloperoxidase, elastase, and dsDNA in Lewis lung cancer (LLC) and Hepa1-6 tumor-bearing mice. Furthermore, liraglutide downregulated NETs and reactive oxygen species (ROS) of neutrophils in the tumor microenvironment. Functionally, in vitro experiments showed that liraglutide reduced NET formation by inhibiting ROS. In addition, we showed that liraglutide enhanced the anti-tumoral efficiency of programmed cell death-1 (PD-1) inhibition in LLC and Hepa1-6 tumor-bearing C57BL/6 mice. However, the removal of NETs significantly weakened the antitumor efficiency of liraglutide. We further demonstrated that the long-term antitumor CD8+ T cell responses induced by the combination therapy rejected rechallenges by respective tumor cell lines. Taken together, our findings suggest that liraglutide may promote the anti-tumoral efficiency of PD-1 inhibition by reducing NETs in lung and liver cancers.

Late Presentation of Oral Chronic Graft Versus Host Disease Manifesting As Hyperkeratotic Plaque: A Case Report

Hematopoietic stem cell transplantation is the only curative intervention for myelodysplastic syndrome, with graft-versus-host disease (GVHD) being a frequently encountered consequence. GVHD is classified as acute (aGVHD) or chronic (cGVHD). The oral cavity is the most impacted by chronic. Oral manifestations of cGVHD are variable and include plaque, Wickham striae, and lichenoid patches. In order to prevent malignant misdiagnosis, the 2014 NIH consensus report decided to exclude white plaque as a diagnostic indicator for oral cGVHD. Nevertheless, it is still possible to classify a white plaque lesion as cGVHD through histological confirmation. The performance of a biopsy should be undertaken following meticulous consideration and a thorough evaluation of the associated risks and benefits. The in-depth review of oral cancer risk assessment is crucial, necessitating a careful review of multiple factors to accurately estimate the likelihood of malignant transformation in individuals with oral cGVHD. This report describes a case of oral cGVHD manifesting as hyperkeratotic plaque lesions confirmed by histopathology in a 62-year-old man who received an allogeneic hematopoietic stem cell transplant over a decade ago.

Deregulation of New Cell Death Mechanisms in Leukemia

Hematological malignancies are among the top five most frequent forms of cancer in developed countries worldwide. Although the new therapeutic approaches have improved the quality and the life expectancy of patients, the high rate of recurrence and drug resistance are the main issues for counteracting blood disorders. Chemotherapy-resistant leukemic clones activate molecular processes for biological survival, preventing the activation of regulated cell death pathways, leading to cancer progression. In the past decade, leukemia research has predominantly centered around modulating the well-established processes of apoptosis (type I cell death) and autophagy (type II cell death). However, the development of therapy resistance and the adaptive nature of leukemic clones have rendered targeting these cell death pathways ineffective. The identification of novel cell death mechanisms, as categorized by the Nomenclature Committee on Cell Death (NCCD), has provided researchers with new tools to overcome survival mechanisms and activate alternative molecular pathways. This review aims to synthesize information on these recently discovered RCD mechanisms in the major types of leukemia, providing researchers with a comprehensive overview of cell death and its modulation.

Analyzing Blood Cells of High-Risk Myelodysplastic Syndrome Patients Using Interferometric Phase Microscopy and Fluorescent Flow Cytometry

Myelodysplastic syndromes (MDSs) are a group of potentially deadly diseases that affect the morphology and function of neutrophils. Rapid diagnosis of MDS is crucial for the initiation of treatment that can vastly improve disease outcome. In this work, we present a new approach for detecting morphological differences between neutrophils isolated from blood samples of high-risk MDS patients and blood bank donors (BBDs). Using fluorescent flow cytometry, neutrophils were stained with 2',7'-dichlorofluorescin diacetate (DCF), which reacts with reactive oxygen species (ROS), and Hoechst, which binds to DNA. We observed that BBDs possessed two cell clusters (designated H and L), whereas MDS patients possessed a single cluster (L). Later, we used FACS to sort the H and the L cells and used interferometric phase microscopy (IPM) to image the cells without utilizing cell staining. IPM images showed that H cells are characterized by low optical path delay (OPD) in the nucleus relative to the cytoplasm, especially in cell vesicles containing ROS, whereas L cells are characterized by low OPD in the cytoplasm relative to the nucleus and no ROS-containing vesicles. Moreover, L cells present a higher average OPD and dry mass compared to H cells. When examining neutrophils from MDS patients and BBDs by IPM during flow, we identified ~20% of cells as H cells in BBDs in contrast to ~4% in MDS patients. These results indicate that IPM can be utilized for the diagnosis of complex hematological pathologies such as MDS.

Neutrophil hitchhiking nanoparticles enhance bacteria-mediated cancer therapy via NETosis reprogramming

Bacteria have shown great potential in anti-tumor treatment, and an attenuated strain of Salmonella named VNP20009 has been shown to be safe in clinical trials. However, colonized bacteria recruit neutrophils into the tumor, which release NETs to capture and eliminate bacteria, compromising bacterial-based tumor treatment. In this study, we report a neutrophil hitchhiking nanoparticles (SPPS) that block the formation of NET to enhance bacteria-mediated tumor therapy. In the 4 T1 tumor-bearing mouse model, following 24 h of bacterial therapy, there was an approximately 3.0-fold increase in the number of neutrophils in the bloodstream, while the amount of SPPS homing to tumor tissue through neutrophil hitchhiking increased approximately 2.0-fold. It is worth noting that the NETs in tumors significantly decreased by approximately 2.0-fold through an intracellular ROS scavenging-mediated NETosis reprogramming, thereby increasing bacterial vitality by 1.9-fold in tumors. More importantly, the gene drug (siBcl-2) loaded in SPPS can be re-encapsulated in apoptotic bodies by reprogramming neutrophils from NETosis to apoptosis, and enable the redelivery of drugs to tumor cells, further boosting the antitumor efficacy with a synergistic effect, resulting in about 98% tumor inhibition rate and 90% survival rate.

Infectious Complications in Patients with Myelodysplastic Syndromes: A Report from the Düsseldorf MDS Registry

Despite notable advancements in infection prevention and treatment, individuals with hematologic malignancies still face the persistent threat of frequent and life-threatening complications. Those undergoing chemotherapy or other disease-modifying therapies are particularly vulnerable to developing infectious complications, increasing the risk of mortality. Myelodysplastic syndromes (MDS) predominantly affect the elderly, with the incidence rising with age and peaking at around 70 years. Patients with MDS commonly present with unexplained low blood-cell counts, primarily anemia, and often experience varying degrees of neutropenia as the disease progresses. In our subsequent retrospective study involving 1593 patients from the Düsseldorf MDS Registry, we aimed at outlining the incidence of infections in MDS patients and identifying factors contributing to heightened susceptibility to infectious complications in this population.

No indication of aberrant neutrophil extracellular trap release in indolent or advanced systemic mastocytosis

In disease states with chronic inflammation, there is a crosstalk between mast cells and neutrophil granulocytes in the inflamed microenvironment, which may be potentiated by tryptase. In systemic mastocytosis (SM), mast cells are constitutively active and tryptase is elevated in blood. Mast cell activation in SM leads to symptoms from various organs depending on where the active mast cells reside, for example, palpitations, flush, allergic symptoms including anaphylactic reactions, and osteoporosis. Whether neutrophil function is altered in SM is not well understood. In the current study, we assessed nucleosomal citrullinated histone H3 (H3Cit-DNA) as a proxy for neutrophil extracellular trap release in plasma from 55 patients with indolent and advanced SM. We observed a strong trend towards a correlation between leukocyte count, eosinophil count and neutrophil count and H3Cit-DNA levels in patients with advanced SM but not in indolent SM; however, no differences in H3Cit-DNA levels in SM patients compared with healthy controls. H3Cit-DNA levels did not correlate with SM disease burden, tryptase levels, history of anaphylaxis or presence of cutaneous mastocytosis; thus, there is no evidence of a general neutrophil extracellular trap release in SM. Interestingly, H3Cit-DNA levels and leukocyte counts were elevated in a subgroup of SM patients with aberrant mast cell CD2 expression, which warrants further investigation. In conclusion, we found no evidence of global increase in neutrophil extracellular trap release in SM.

Myelodysplastic neoplasm-associated U2AF1 mutations induce host defense defects by compromising neutrophil chemotaxis

Myelodysplastic neoplasm (MDS) is a hematopoietic stem cell disorder that may evolve into acute myeloid leukemia. Fatal infection is among the most common cause of death in MDS patients, likely due to myeloid cell cytopenia and dysfunction in these patients. Mutations in genes that encode components of the spliceosome represent the most common class of somatically acquired mutations in MDS patients. To determine the molecular underpinnings of the host defense defects in MDS patients, we investigated the MDS-associated spliceosome mutation U2AF1-S34F using a transgenic mouse model that expresses this mutant gene. We found that U2AF1-S34F causes a profound host defense defect in these mice, likely by inducing a significant neutrophil chemotaxis defect. Studies in human neutrophils suggest that this effect of U2AF1-S34F likely extends to MDS patients as well. RNA-seq analysis suggests that the expression of multiple genes that mediate cell migration are affected by this spliceosome mutation and therefore are likely drivers of this neutrophil dysfunction.

Myelodysplastic Syndromes: New Methods of Diagnosis, Prognostication, and Treatment

BACKGROUND

Myelodysplastic syndromes (MDS) are malignant diseases arising from hematopoietic stem cells. Their overall incidence is 4 cases per 100 000 persons per year, and they are usually diagnosed when evaluating cytopenia. The median survival time is three years. Myelodysplastic syndromes take a variable course; one-quarter of patients go on to develop acute leukemia.

METHODS

This review is based on publications retrieved by a selective search of the literature from 2013 to 2022, including relevant guidelines, in the PubMed database. The time period was chosen to reflect developments since the publication of the latest EHA guidelines in 2013.

RESULTS

The gold standard of diagnosis is cytomorphology of the blood and bone marrow, supplemented by banding cytogenetics, histomorphology, and somatic mutation analyses. The new classification proposed by the WHO incorporates the molecular and cytogenetic findings. The Molecular International Prognostic Scoring System (IPSS-M), which takes somatic mutations into account, is now available as an aid to prognostication. Quality of life evaluation with standardized instruments is helpful in many ways. Low-risk patients are treated supportively with erythrocyte transfusions and iron chelation therapy. Erythropoietin-a can be given to patients whose erythropoietin level is less than 200ng/mL, lenalidomide to those with a 5q deletion, and luspatercept to those with an SF3B1 mutation. High-risk patients should be evaluated as early as possible for allogeneic hematopoietic stem cell transplantation with curative intent. 5-azacytidine improves outcomes in patients for whom stem cell transplantation is not suitable.

CONCLUSION

Once a precise diagnosis has been established, new prognostic instruments such as the IPSS-M enable risk-adapted treatment based on the biological aspects of the patient's disease as well as his or her age and comorbidities.