G-CSF - A double edge sword in neutrophil mediated immunity

Simple dysmood disorder, a mild subtype of major depression, is not an inflammatory condition: Depletion of the compensatory immunoregulatory system

BACKGROUND

A recent study conducted by the laboratory of the first author revealed that major depression is composed of two distinct subtypes: major dysmood disorder (MDMD) and simple dysmood disorder (SDMD). The latter is a less severe phenotype with fewer aberrant biological pathways. MDMD, but not SDMD, patients were identified to have highly sensitized cytokine/growth factor networks using stimulated whole blood cultures. However, no information regarding serum cytokines/chemokines/growth factors in SDMD is available.

OBJECTIVES

This case-control study compares 48 serum cytokines/chemokines/growth factors in academic students with SDMD (n = 64) and first episode (FE)-SDMD (n = 47) to those of control students (n = 44) using a multiplex assay.

FINDINGS

Both FE-SDMD and SDMD exhibited a notable inhibition of immune profiles, such as the compensatory immunoregulatory response system (CIRS) and alternative M2 macrophage and T helper-2 (Th-2) profiles. We observed a substantial reduction in the serum concentrations of five proteins: interleukin (IL)-4, IL-10, soluble IL-2 receptor (sIL-2R), IL-12p40, and macrophage colony-stimulating factor. A considerable proportion of the variability observed in suicidal behaviors (26.7 %) can be accounted for by serum IL-4, IL-10, and sIL-2R (all decreased), CCL11 (eotaxin) and granulocyte CSF (both increased). The same biomarkers (except for IL-10), accounted for 25.5 % of the variance in SDMS severity. A significant correlation exists between decreased levels of IL-4 and elevated ratings of the brooding type of rumination.

CONCLUSIONS

SDMD is characterized by the suppression of the CIRS profile, which signifies a disruption of immune homeostasis and tolerance, rather than the presence of an inflammatory response.

Marked exacerbation of resolving macrophage activation syndrome in a patient with adult-onset Still's disease following one dose of granulocyte colony-stimulating factor

Macrophage activation syndrome (MAS) is a frequent complication of adult-onset Still's disease (AOSD) and is characterised by organ dysfunction, cytopenia and coagulopathy. There are few data regarding the use of granulocyte colony-stimulating factor (G-CSF) as a treatment for neutropenia in MAS due to AOSD. This case describes a previously healthy mid-20s patient who was diagnosed with AOSD and subsequently MAS. Although his clinical symptoms and ferritin levels responded well to steroids, interleukin-1 inhibition and Janus kinase inhibition, he developed prolonged and profound neutropenia for which he received one dose of G-CSF. His MAS flared markedly, requiring intensive immunosuppression and significantly prolonging his hospital stay. This report illustrates that G-CSF carries the risk of worsening inflammation leading to MAS, particularly in auto-inflammatory conditions such as AOSD.

Common molecular profile of multiple structurally distinct warfare arsenicals in causing cutaneous chemical vesicant injury

Skin exposure to arsenicals such as lewisite and phenylarsine oxide leads to severe cutaneous damage. Here, we characterized the molecular pathogenesis of skin injury caused by additionally structurally distinct warfare arsenicals including diphenylchlorarsine (DPCA), diphenylcyanoarsine (DPCYA), diethylchloroarsine (DECA). Cutaneous exposure to DPCA/DPCYA showed marked increase in skin erythema and edema at 6 and 24 h followed by scar formation at 72 h, while DECA did not produce such visual injuries in mouse skin. Clinical observations showed significant increase in Draize score and skin bi-fold thickness in a time-dependent manner. DPCA or DPCYA-exposed skin histology revealed highly inflamed hypodermal areas with infiltrated immune cells at 6 and 24 h, however, epidermal cell necrosis was seen at 72 h. Significantly high number of macrophage infiltration observed at 6 h, whereas peak neutrophil infiltration occurred at 72 h. Number of micro-blisters also increased. However, these effects were nonsignificant following topical DECA exposure. RT-PCR confirmed augmented inflammatory responses in the skin challenged with both DPCA/DPCYA, which accompanied increased ROS and unfolded protein response (UPR) signaling. DECA also increased ROS with changes in UPR. Disrupted tight (Yap/ZO-1) and adherens (Yap/α-Catenin) junction proteins underlie time-dependent apoptotic cell death of epidermal keratinocytes. Thus, these studies identify arsenicals-manifested signaling pathways similar to those of lewisite.

Activated platelet membrane vesicles for broad-spectrum bacterial pulmonary infections management

The development of new antibiotics has lagged behind the rapid evolution of bacterial resistance, prompting the exploration of alternative antimicrobial strategies. Host-directed therapy (HDT) has emerged as a promising approach by harnessing innate immune system's natural defense mechanisms, which reduces reliance on antibiotics, and mitigates the development of resistance. Building on the important role of platelets in host immunity, activated platelet membrane vesicles (PLTv) are developed here as a host-directed therapy for broad-spectrum antibacterial infection management, leveraging several key mechanisms of action. PLTv neutralizes bacterial toxins, thereby reducing cytotoxicity. The presence of platelet receptors on PLTv enables them to act as decoys, binding bacteria through receptor interactions and facilitating their phagocytosis by neutrophils and macrophages. Additionally, PLTv bound to bacteria promote the formation of neutrophil extracellular traps (NETs), enhancing the immune system's ability to trap and kill bacteria. In mouse models of pulmonary infections caused by the Methicillin-resistant Staphylococcus aureus, P. aeruginosa, and A. baumannii, administration of PLTv significantly reduces bacterial counts in the lungs and protects against mortality. Taken together, the present work highlights PLTv as a promising host-directed therapy for combating broad-spectrum pulmonary drug-resistant bacterial infections, leveraging their ability to neutralize toxins, act as decoys, promote phagocytosis, and facilitate NETs formation.

Resolution of Pyoderma Gangrenosum During Adjuvant Breast Cancer Therapy

Background/Objectives: Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis characterized by rapidly developing, painful ulcerative lesions. It exhibits pathergy, a phenomenon in which minor trauma or injury to the skin triggers an exaggerated inflammatory response. This leads to the development of new skin lesions or the worsening of existing ones. Treatment typically involves a combination of corticosteroids and immunosuppressive agents. However, even with effective therapy, the overall management of pyoderma gangrenosum remains challenging, and wound healing can be prolonged. The development of pyoderma gangrenosum after breast cancer surgery is rare, and its presence complicates the treatment of patients requiring additional oncologic therapy. In particular, the effect of radiation on these lesions is not well documented. Given the known skin toxicity of radiotherapy and its negative impact on wound healing, the use of adjuvant breast radiation raises significant concerns in this context. Methods: We present the case of a 66-year-old female with Stage IIB invasive ductal carcinoma of the left breast who developed postoperative pyoderma gangrenosum after breast-conserving surgery. The patient was treated with systemic corticosteroids and cyclosporine, and then subsequently underwent standard-of-care adjuvant chemotherapy and radiation. Results: During therapy, she demonstrated rapid resolution of her pyoderma gangrenosum without experiencing excess skin toxicity. Conclusions: While the literature on the direct application of radiation in pyoderma gangrenosum is limited, our case provides evidence supporting the safety of radiation therapy in oncologic cases complicated by this disease. In addition to receiving the benefit of adjuvant therapy for her breast cancer, our patient demonstrated an improvement in her postoperative PG with no adverse skin effects.

Secondary Neutropenias

Neutrophils are a critical component of immunity, particularly against bacteria and other pathogens, but also in inflammation and tissue repair. As a consequence, individuals with neutropenia, defined by a reduction in absolute neutrophil counts, exhibit a strong propensity to severe infections that typically present with muted symptoms. Neutropenias encompass a heterogeneous set of disorders, comprising primary neutropenias, in which specific genes are mutated, and the more common secondary neutropenias, which have diverse non-genetic causes. These include hematological and other cancers, involving both direct effects of the cancer itself and indirect impacts via the chemotherapeutic, biological agents and cell-based approaches used for treatment. Other significant causes of secondary neutropenias are non-chemotherapeutic drugs, autoimmune and other immune diseases, infections and nutrient deficiencies. These collectively act by impacting neutrophil production in the bone marrow and/or destruction throughout the body. This review describes the biological and clinical manifestations of secondary neutropenias, detailing their underlying causes and management, with a discussion of alternative and emerging therapeutic approaches.

Serotonin receptor 5-HT7 modulates inflammatory-associated functions of macrophages

The hormone and neurotransmitter serotonin regulates numerous physiological functions within the central nervous system and in the periphery upon binding to specific receptors. In the periphery, the serotonin receptor 7 (5-HT7R) is expressed on different immune cells including monocytes and macrophages. To investigate the impact of 5-HT7R-mediated signaling on macrophage properties, we used human THP-1 cells and differentiated them into pro-inflammatory M1- and anti-inflammatory M2-like macrophages. Pharmacological 5-HT7R activation with the specific agonist LP-211 especially modulates morphology of M1-like macrophages by increasing the number of rounded cells. Furthermore, 5-HT7R stimulation results in significantly reduced phagocytic and migratory ability of M1-like macrophages. Noteworthy, LP-211 treatment leads to changes in secretory properties of all macrophage types with the highest effects obtained for M0- and M2c-like macrophages. Finally, the importance of 5-HT7R for regulation of phagocytosis was confirmed in human primary CD14+ cells. These results indicate that 5-HT7R activation selectively impairs basic functions of macrophages and might thus be a new access point for the modulation of macrophage responses in the future treatment of inflammatory diseases.

Post-transplant G-CSF impedes engraftment of gene-edited human hematopoietic stem cells by exacerbating p53-mediated DNA damage response

Granulocyte-colony-stimulating factor (G-CSF) is commonly used to accelerate recovery from neutropenia following chemotherapy and autologous transplantation of hematopoietic stem and progenitor cells (HSPCs) for malignant disorders. However, its utility after ex vivo gene therapy in human HSPCs remains unexplored. We show that administering G-CSF from day 1 to 14 post-transplant impedes engraftment of CRISPR-Cas9 gene-edited human HSPCs in murine xenograft models. G-CSF affects gene-edited HSPCs through a cell-intrinsic mechanism, causing proliferative stress and amplifying the early p53-mediated DNA damage response triggered by Cas9-mediated DNA double-strand breaks. This underscores a threshold mechanism where p53 activation must reach a critical level to impair cellular function. Transiently inhibiting p53 or delaying the initiation of G-CSF treatment to day 5 post-transplant attenuates its negative impact on gene-edited HSPCs. The potential for increased HSPC toxicity associated with post-transplant G-CSF administration in CRISPR-Cas9 autologous HSPC gene therapy warrants consideration in clinical trials.

The type 2 immune response in gut homeostasis and parasite transmission in malaria

Malaria predisposes to concomitant bacteremia, resulting in increased mortality risk. Previous studies indicated that malaria causes structural changes in the intestine, induces tolerogenic immune responses, inhibits neutrophil recruitment, suppresses innate synthesis of IFN-γ, dysregulates mast cells (MCs) and basophils, and induces Th2-type immune responses. These can reduce parasite control while increasing enteropathogenic dissemination. Moreover, there is growing evidence that Th2 immunity, while protecting the host from overwhelming inflammation, may also contribute to increased parasite transmission. This review explores the roles of the regulatory immune response in bacterial coinfections and parasite transmission in malaria.

Gene expression responses of CF airway epithelial cells exposed to elexacaftor/tezacaftor/ivacaftor suggest benefits beyond improved CFTR channel function

The combination of elexacaftor/tezacaftor/ivacaftor (ETI, Trikafta) reverses the primary defect in cystic fibrosis (CF) by improving CFTR-mediated Cl- and HCO3- secretion by airway epithelial cells (AECs), leading to improved lung function and less frequent exacerbations and hospitalizations. However, studies have shown that CFTR modulators like ivacaftor, a component of ETI, have numerous effects on CF cells beyond improved CFTR channel function. Because little is known about the effect of ETI on CF AEC gene expression, we exposed primary human AEC to ETI for 48 h and interrogated the transcriptome by RNA-seq and qPCR. ETI increased CFTR Cl- secretion, and defensin gene expression (DEFB1), an observation consistent with reports of decreased bacterial burden in the lungs of people with CF (pwCF). ETI decreased MMP10 and MMP12 gene expression, suggesting that ETI may reduce proteolytic-induced lung destruction in CF. ETI also reduced the expression of the stress response gene heme oxygenase (HMOX1). qPCR analysis confirmed DEFB1, HMOX1, MMP10, and MMP12 gene expression results observed by RNA-seq. Gene pathway analysis revealed that ETI decreased inflammatory signaling, cellular proliferation, and MHC class II antigen presentation. Collectively, these findings suggest that the clinical observation that ETI reduces lung infections in pwCF is related in part to drug-induced increases in DEFB1 and that ETI may reduce lung damage by reducing MMP10 and MMP12 gene expression. Moreover, pathway analysis also identified several other genes responsible for the ETI-induced reduction in inflammation observed in pwCF.NEW & NOTEWORTHY Gene expression responses by CF AECs exposed to ETI suggest that in addition to improving CFTR channel function, ETI is likely to enhance resistance to bacterial infection by increasing levels of beta-defensin 1 (hBD-1). ETI may also reduce lung damage by suppressing MMP10 and MMP12 and reduce airway inflammation by repressing proinflammatory cytokine secretion by CF AECs.

Endolysin NC5 improves early cloxacillin treatment in a mouse model of Streptococcus uberis mastitis

Streptococcus uberis frequently causes bovine mastitis, an infectious udder disease with significant economic implications for dairy cows. Conventional antibiotics, such as cloxacillin, sometimes have limited success in eliminating S. uberis as a stand-alone therapy. To address this challenge, the study objective was to investigate the VersaTile engineered endolysin NC5 as a supplemental therapy to cloxacillin in a mouse model of bovine S. uberis mastitis. NC5 was previously selected based on its intracellular killing and biofilm eradicating activity. To deliver preclinical proof-of-concept of this supplemental strategy, lactating mice were intramammarily infected with a bovine S. uberis field isolate and subsequently treated with cloxacillin (30.0 μg) combined with either a low (23.5 μg) or high (235.0 μg) dose of NC5. An antibiotic monotherapy group, as well as placebo treatment, was included as controls. Two types of responders were identified: fast (n = 17), showing response after 4-h treatment, and slow (n = 10), exhibiting no clear response at 4 h post-treatment across all groups. The high-dose combination therapy in comparison with placebo treatment impacted the hallmarks of mastitis in the fast responders by reducing (i) the bacterial load 13,000-fold (4.11 ± 0.78 Δlog10; p < 0.001), (ii) neutrophil infiltration 5.7-fold (p > 0.05), and (iii) the key pro-inflammatory chemokine IL-8 13-fold (p < 0.01). These mastitis hallmarks typically followed a dose response dependent on the amount of endolysin added. The current in vivo study complements our in vitro data and provides preclinical proof-of-concept of NC5 as an adjunct to intramammary cloxacillin treatment. KEY POINTS: • Engineered endolysin NC5 was preclinically evaluated as add-on to cloxacillin treatment. • Two types of mice (slow and fast responding) were observed. • The add-on treatment decreased bacterial load, neutrophil influx, and pro-inflammatory mediators.

Major depressive disorder, neuroticism, suicidal behaviors, and depression severity are associated with cytokine networks and their intricate interactions with metabolic syndrome

OBJECTIVES

To identify alterations in the immune profiles in outpatients with major depression (MDD), and its associations with key features, such as suicidal ideation, neuroticism, cognitive symptoms, and the depression phenome while accounting for metabolic syndrome (MetS).

METHODS

In this case-control study, we assayed 48 serum cytokines, chemokines, and growth factors in 67 healthy controls and 66 MDD outpatients. Around 50 % of the outpatient MDD and control participants had a diagnosis of MetS.

RESULTS

Ten differentially expressed proteins (DEPs) were upregulated in outpatient MDD (i.e., CXCL12, tumor necrosis factor [TNF]β, platelet-derived growth factor [PDGF], CCL11, interleukins [IL]9, IL4, CCL5, CCL2, CCL4, IL1 receptor antagonist [IL1RN]), indicating an immune and defense response. Six DEPs were downregulated (vascular endothelial growth factor A [VEGFA], IL12, CCL3, colony stimulating factor [CSF]1, IL1B, nerve growth factor [NGF]), indicating lowered neurogenesis and neuron death regulation. Significant interactions between outpatient MDD and MetS caused a) substantial increases in IL4, IL17, TNF, TNFB, CCL2, CCL5, PDGF, IL1RN; and b) downregulation of VEGFA and FGF. A large part of the variance in neuroticism (26 %), suicidal behaviors (23 %), and the MDD phenome (31 %) was predicted by immunological data and interactions between MetS and CCL5, TNFB or VEGFA.

CONCLUSION

Outpatient MDD is characterized by a cytokine profile with neurotoxic potential which partly explains neuroticism, suicidal behaviors, and the phenome's severity. Lowered IL-10 and activated cytokine profiles with neurotoxic potential are characteristics of outpatient MDD and other depression phenotypes, including severe first-episode inpatient MDD. The presence of MetS in outpatient MDD considerably activates immune profiles with neurotoxic potential. Consequently, immune studies in MDD should always be performed in subjects with and without MetS.

scRNA-seq profiling of human granulocytes reveals expansion of developmentally flexible neutrophil precursors with mixed neutrophil and eosinophil properties in asthma

Neutrophils and eosinophils share common hematopoietic precursors and usually diverge into distinct lineages with unique markers before being released from their hematopoietic site, which is the bone marrow (BM). However, previous studies identified an immature Ly6g(+) Il-5Rα(+) neutrophil population in mouse BM, expressing both neutrophil and eosinophil markers suggesting hematopoietic flexibility. Moreover, others have reported neutrophil populations expressing eosinophil-specific cell surface markers in tissues and altered disease states, confusing the field regarding eosinophil origins, function, and classification. Despite these reports, it is still unclear whether hematopoietic flexibility exists in human granulocytes. To answer this, we utilized single-cell RNA sequencing and cellular indexing of transcriptomes and epitopes by sequencing to profile human BM and circulating neutrophils and eosinophils at different stages of differentiation and determine whether neutrophil plasticity plays role in asthmatic inflammation. We show that immature metamyelocyte neutrophils in humans expand during severe asthmatic inflammation and express both neutrophil and eosinophil markers. We also show an increase in trilobed eosinophils with mixed neutrophil and eosinophil markers in allergic asthma and that interleukin-5 promotes differentiation of immature blood neutrophils into trilobed eosinophilic phenotypes, suggesting a mechanism of emergency granulopoiesis to promote myeloid inflammatory or remodeling response in patients with chronic asthma. By providing insights into unexpectedly flexible granulocyte biology and demonstrating emergency hematopoiesis in asthma, our results highlight the importance of granulocyte plasticity in eosinophil development and allergic diseases.

UFMylation is involved in serum inflammatory cytokines generation and splenic T cell activation induced by lipopolysaccharide

UFMylation, a novel ubiquitin-like protein modification system, has been recently found to be activated in inflammation. However, the effects of UFMylation activation on inflammation in vivo remains unclear. In the present study, we generated a UFMylation activated mice using transgenic (TG) techniques. Lipopolysaccharide (LPS) was used to induce systemic inflammation in both TG and non-transgenic (NTG) mice. Serum cytokines were detected using a Mouse Cytokine Array, and the proportions of splenic NK, B and T cells were determined by using flow cytometry. We found that TG mice showed increased serum G-CSF, TNF RII and decreased serum TCA-3, CD30L, bFGF, IL-15 and MIG compared with NTG mice at baseline. Furthermore, serum cytokines in TG mice exhibited different responses to LPS compared to NTG mice. LPS up-regulated serum TNF RII, G-CSF, MCP-5, RANTES, KC, BLC, MIG and down-regulated IL-1b, IL-2, IL-3, IL-4, IL-5, IL-7, IL-10, IL-12p40, IL-15, IL-17, IFN-γ, TCA-3, Eotaxin-2, LIX, MCP-1, TNFα, GM-CSF in NTG mice, whereas LPS up-regulated G-CSF, MCP-5, RANTES, KC, BLC, MIG, ICAM-1, PF4, Eotaxin, CD30L, MIP-1a, TNFRI and down-regulated IL-1b, IL-3, LIX, MCP-1, TNFα, GM-CSF in TG mice. Data from flow cytometry indicated that LPS significantly reduced the percentages of NK and NKT cells in NTG mice, whereas UFMylation activation inhibited LPS-induced NKT cell decrease. The proportions of B cells, total CD4+ and total CD8+ T cells were comparable between TG and NTG mice in response to LPS treatment, whereas the percentages of CD4+CD69+ and CD8+CD69+T cells were lower in TG mice. These findings suggest that UFMylation may alter LPS-induced serum cytokine profile and participate in splenic T cell activation in vivo.

Allyl isothiocyanate exacerbates acute toxoplasmosis through inhibition of inflammatory cytokines

Allyl isothiocyanate (AITC) is a natural product commonly used in food preservation and pharmaceutical applications. Toxoplasmosis, caused by the protozoan pathogen Toxoplasma gondii, is prevalent globally while the impact of AITC on toxoplasmosis is unclear. We explored the effect of AITC on acute toxoplasmosis. We infected C57BL/6 mice with T. gondii type I RH strain following AITC administration. On the 4th day after infection, which corresponds to the initial stage of infection, we collected serum for the determination of inflammatory cytokine levels. The mice serum of the AITC-administered group contained significantly lower levels of granulocyte colony-stimulating factor, interferon-gamma, interleukin (IL)-23 subunit p19, IL-4, IL-6, and monocyte chemoattractant protein-1. The lifespan of the mice in the AITC-administered group was significantly reduced. In vitro experiments showed that AITC promoted the proliferation of intracellular T. gondii accompanied by the inhibition of IL-4, IL-1β, and IL-6 production in RAW264.7 macrophages. Our results showed that AITC facilitated T. gondii infection in the early stage by inhibiting the production of several inflammatory cytokines.

Evaluation of the immune response of peripheral blood mononuclear cells cultured on Ti6Al4V-ELI polished or etched surfaces

Introduction

While titanium and its alloys exhibit excellent biocompatibility and corrosion resistance, their polished surfaces can hinder fast and effective osseointegration and other biological processes, such as angiogenesis, due to their inert and hydrophobic properties. Despite being commonly used for orthopedic implants, research focuses on developing surface treatments to improve osseointegration, promoting cell adhesion and proliferation, as well as increasing protein adsorption capacity. This study explores a chemical treatment intended for titanium-based implants that enhances tissue integration without compromising the mechanical properties of the Ti6Al4V substrate. However, recognizing that inflammation contributes to nearly half of early implant failures, we assessed the impact of this treatment on T-cell viability, cytokine production, and phenotype.

Methods

Ti6Al4V with extra low interstitial (ELI) content discs were treated with hydrofluoric acid followed by a controlled oxidation step in hydrogen peroxide that creates a complex surface topography with micro- and nano-texture and modifies the chemistry of the surface oxide layer. The acid etched surface contains an abundance of hydroxyl groups, crucial for promoting bone growth and apatite precipitation, while also enabling further functionalization with biomolecules.

Results

While cell viability remained high in both groups, untreated discs triggered an increase in Th2 cells and a decrease of the Th17 subset. Furthermore, peripheral blood mononuclear cells exposed to untreated discs displayed a rise in various pro-inflammatory and anti-inflammatory cytokines compared to the control and treated groups. Conversely, the treated discs showed a similar profile to the control, both in terms of immune cell subset frequencies and cytokine secretion.

Discussion

The dysregulation of the cytokine profile upon contact with untreated Ti6Al4V-ELI discs, namely upregulation of IL-2 could be responsible for the decrease in Th17 frequency, and thus might contribute to implant-associated bacterial infection. Interestingly, the chemical treatment restores the immune response to levels comparable to the control condition, suggesting the treatment's potential to mitigate inflammation by enhancing biocompatibility.

Association of Granulocyte Colony-Stimulating Factor Treatment with Risk of Brain Metastasis in Advanced Stage Breast Cancer

The routine use of granulocyte colony-stimulating factor (GCSF) is not recommended for the prevention or treatment of chemotherapy-induced neutropenia or febrile neutropenia because risks associated with certain types of cancers, distant organ metastases, and primary tumor growth cannot be excluded. We examined the association between GCSF use and the incidence of brain metastasis (BM), as well as BM-free survival (BMFS). This retrospective cohort study included 121 stage IV breast cancer patients without confirmed BM at the time of diagnosis and who received at least one course of systematic chemotherapy or target therapy at a tertiary teaching hospital between 1 January 2014 and 31 December 2022. The effect of GCSF use on BM was assessed with other confounding factors in Cox regression analyses. In this retrospective cohort, patients who received GCSF treatment had a significantly higher incidence of BM than those who did not (34.9% vs. 13.8%, p = 0.011). Univariate Cox regression analysis showed that GCSF use, menopause status, hormone treatment, HER2 treatment, cumulative dosage, dosage density, and neutropenia were independent risk factors for BMFS (p < 0.05). GCSF users had a higher risk of BM (adjusted HR: 2.538; 95% CI: 1.127-5.716, p = 0.025) than nonusers. BM risk was significantly associated with those with neutropenia (RR: 1.84, 95% CI: 1.21, 2.80) but not with those without neutropenia (RR: 0.59, 95% CI: 0.41-0.84, Interaction p-value < 0.05). The higher the dose density of GCSF, the higher the risk compared with those who do not use GCSF (p for trend < 0.01). These preliminary results suggest that GCSF is associated with BM in patients with stage IV breast cancer who did not have BM at initial diagnosis. Further comprehensively designed large-scale observational studies are needed to confirm our preliminary results.

Nasal microbionts differentially colonize and elicit cytokines in human nasal epithelial organoids

Nasal colonization by Staphylococcus aureus or Streptococcus pneumoniae is associated with an increased risk of infection by these pathobionts, whereas nasal colonization by Dolosigranulum species is associated with health. Human nasal epithelial organoids (HNOs) physiologically recapitulate human nasal respiratory epithelium with a robust mucociliary blanket. We reproducibly monocolonized HNOs with these three bacteria for up to 48 hours with varying kinetics across species. HNOs tolerated bacterial monocolonization with localization of bacteria to the mucus layer and minimal cytotoxicity compared to uncolonized HNOs. Human nasal epithelium exhibited both species-specific and general cytokine responses, without induction of type I interferons, consistent with colonization rather than infection. Only live S. aureus colonization induced IL-1 family cytokines, suggestive of inflammasome signaling. D. pigrum and live S. aureus decreased CXCL10, whereas S. pneumoniae increased CXCL11, chemokines involved in antimicrobial responses. HNOs are a compelling model system to reveal host-microbe dynamics at the human nasal mucosa.

Neutrophils in the premetastatic niche: key functions and therapeutic directions

Metastasis has been one of the primary reasons for the high mortality rates associated with tumours in recent years, rendering the treatment of current malignancies challenging and representing a significant cause of recurrence in patients who have undergone surgical tumour resection. Halting tumour metastasis has become an essential goal for achieving favourable prognoses following cancer treatment. In recent years, increasing clarity in understanding the mechanisms underlying metastasis has been achieved. The concept of premetastatic niches has gained widespread acceptance, which posits that tumour cells establish a unique microenvironment at distant sites prior to their migration, facilitating their settlement and growth at those locations. Neutrophils serve as crucial constituents of the premetastatic niche, actively shaping its microenvironmental characteristics, which include immunosuppression, inflammation, angiogenesis and extracellular matrix remodelling. These characteristics are intimately associated with the successful engraftment and subsequent progression of tumour cells. As our understanding of the role and significance of neutrophils in the premetastatic niche deepens, leveraging the presence of neutrophils within the premetastatic niche has gradually attracted the interest of researchers as a potential therapeutic target. The focal point of this review revolves around elucidating the involvement of neutrophils in the formation and shaping of the premetastatic niche (PMN), alongside the introduction of emerging therapeutic approaches aimed at impeding cancer metastasis.

Myeloperoxidase-deficient mice exposed to Zymosan exhibit severe neutrophilia and anemia with enhanced granulopoiesis and reduced erythropoiesis, accompanied by pulmonary inflammation

We previously reported that myeloperoxidase-deficient (MPO-/-) mice develop more severe neutrophil-rich lung inflammation than wild-type mice following intranasal Zymosan administration. Interestingly, we found that these mutant mice with severe lung inflammation also displayed pronounced neutrophilia and anemia, characterized by increased granulopoiesis and decreased erythropoiesis in the bone marrow, compared to wild-type mice. This condition was associated with higher concentrations of granulocyte-colony stimulating factor (G-CSF) in both the lungs and serum, a factor known to enhance granulopoiesis. Neutrophils accumulating in the lungs of MPO-/- mice produced greater amounts of G-CSF than those in wild-type mice, indicating that they are a significant source of G-CSF. In vitro experiments using signal transduction inhibitors and Western blot analysis revealed that MPO-/- neutrophils express higher levels of G-CSF mRNA in response to Zymosan, attributed to the upregulation of the IκB kinase/nuclear factor (NF)-κB pathway and the extracellular-signal-regulated kinase/NF-κB pathway. These findings highlight MPO as a critical regulator of granulopoiesis and erythropoiesis in inflamed tissues.

Gene expression responses of CF airway epithelial cells exposed to elexacaftor/tezacaftor/ivacaftor (ETI) suggest benefits beyond improved CFTR channel function

The combination of elexacaftor/tezacaftor/ivacaftor (ETI, Trikafta) reverses the primary defect in Cystic Fibrosis (CF) by improving CFTR mediated Cl - and HCO 3 - secretion by airway epithelial cells (AEC), leading to improved lung function and less frequent exacerbations and hospitalizations. However, studies have shown that CFTR modulators like ivacaftor, a component of ETI, has numerous effects on CF cells beyond improved CFTR channel function. Because little is known about the effect of ETI on CF AEC gene expression we exposed primary human AEC to ETI for 48 hours and interrogated the transcriptome by RNA-seq and qPCR. ETI increased defensin gene expression ( DEFB1 ) an observation consistent with reports of decreased bacterial burden in the lungs of people with CF (pwCF). ETI also decreased MMP10 and MMP12 gene expression, suggesting that ETI may reduce proteolytic induced lung destruction in CF. ETI also reduced the expression of the stress response gene heme oxygenase ( HMOX1 ). qPCR analysis confirmed DEFB1, HMOX1, MMP10 and MMP12 gene expression results observed by RNA-seq. Gene pathway analysis revealed that ETI decreased inflammatory signaling, cellular proliferation and MHC Class II antigen presentation. Collectively, these findings suggest that the clinical observation that ETI reduces lung infections in pwCF is related in part to drug induced increases in DEFB1 , and that ETI may reduce lung damage by reducing MMP10 and MMP12 gene expression, which is predicted to reduce matrix metalloprotease activity. Moreover, pathway analysis also identified several genes responsible for the ETI induced reduction in inflammation observed in people with CF.

New and Noteworthy

Gene expression responses by CF AEC exposed to ETI suggest that in addition to improving CFTR channel function, ETI is likely to increase resistance to bacterial infection by increasing levels of beta defensin 1 (hBD-1). ETI may also reduce lung damage by suppressing MMP10, and reduce airway inflammation by repressing proinflammatory cytokine secretion by AEC cells.

Role of Neutrophils in the Development of Steatotic Liver Disease

This review explores the biological aspects of neutrophils, their contributions to the development of steatotic liver disease, and their potential as therapeutic targets for the disease. Although alcohol-associated and metabolic dysfunction-associated liver diseases originate from distinct etiological factors, the two diseases frequently share excessive lipid accumulation as a common contributor to their pathogenesis, thereby classifying them as types of steatotic liver disease. Dysregulated lipid deposition in the liver induces hepatic injury, triggering the activation of the innate immunity, partially through neutrophil recruitment. Traditionally recognized for their role in microbial clearance, neutrophils have recently garnered attention for their involvement in sterile inflammation, a pivotal component of steatotic liver disease pathogenesis. In conclusion, technological innovations, including single-cell RNA sequencing, have gradually disclosed the existence of various neutrophil subsets; however, how the distinct subsets of neutrophil population contribute differentially to the development of steatotic liver disease remains unclear.

CSF3 aggravates acute exacerbation of pulmonary fibrosis by disrupting alveolar epithelial barrier integrity

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive respiratory disorder characterized by poor prognosis, often presenting with acute exacerbation. The primary cause of death associated with IPF is acute exacerbation of IPF (AE-IPF). However, the pathophysiology of acute exacerbation has not been clearly elucidated yet. This study aims to investigate the underlying pathophysiological molecular mechanism in a mouse AE-PF model. C57BL/6J mice were intratracheally administered bleomycin (BLM, 5 mg/kg) to induce pulmonary fibrosis. After 14 days, lipopolysaccharide (LPS, 2 mg/kg) was injected via the trachea route. Histological assessments, including H&E and Masson staining, as well as inflammatory indicators, were included to evaluate the induction of AE-PF by BLM and LPS in mice. Transcriptomic profiling of pulmonary tissues identified CSF3 as one of the top 10 upregulated DEGs in AE-PF mice. Indeed, administration of exogenous CSF3 protein exacerbated AE-PF in mice. Mechanistically, CSF3 disrupted alveolar epithelial barrier integrity and permeability by regulating specialized cell adhesion complexes such as tight junctions (TJs) and adherens junctions (AJs) via PI3K/p-Akt/Snail pathway, contributing to the aggravation of AE-PF in mice. Moreover, the discovery of elevated sera CSF3 indicated a notable increase in IPF patients during the exacerbation of the disease. Pearson correlation analysis in IPF patients revealed significant positive associations between CSF3 levels and KL-6 levels, LDH levels, CRP levels, respectively. These results provide mechanistic insights into the role of CSF3 in exacerbating of lung fibrotic disease and indicate monitoring CSF3 levels may aid in early clinical decisions for alternative therapy in the management of rapidly progressing IPF.

Subcutaneous injection granulocyte colony-stimulating factor (G-CSF) is superior to intrauterine infusion on patients with recurrent implantation failure: A systematic review and network meta-analysis

Although both subcutaneous injection and intrauterine infusion of granulocyte colony-stimulating factor (G-CSF) have been reported to improve pregnancy outcomes in patients with recurrent implantation failure (RIF), how to administer it is still no consensus. The study aimed to investigate which administration route is optimal. We searched PubMed, Embase, the Cochrane Library (CENTRAL), Web of Science, and China National Knowledge Internet (CNKI) from inception to April 10, 2023, with language in both English and Chinese. The randomized controlled trials (RCTs) compared the effectiveness of G-CSF to treat patients with RIF were included in this network meta-analysis (NMA). The odds ratio (OR) and 95% confidence interval (CI) in pregnancy outcomes (implantation rate, IR; clinical pregnancy rate, CPR; live birth rate, LBR; miscarriage rate, MR; ectopic pregnancy rate, EPR) were summarized by NMA with a random-effects model. A total of 1360 RIF patients from 14 RCTs were included in this NMA, with no publication bias and small sample effects. No direct evidence compared the effectiveness of different administration routes of G-CSF on IR, LBR and MR. Both subcutaneous injection and intrauterine infusion of G-CSF increased the IR (OR = 2.81, 95% CI: 1.10-7.24; OR = 2.15, 95% CI: 1.50-3.07, respectively) and CPR (OR = 2.79, 95% CI: 1.86-4.17; OR = 1.74, 95% CI: 1.30-2.33, respectively) in patients with RIF. According to SUCRA, subcutaneous injection is more likely to be the optimal medication administration route. However, more high-quality studies were also needed to support these, especially IR and LBR.

CSF1R antagonism results in increased supraspinal infiltration in EAE

BACKGROUND

Colony stimulating factor 1 receptor (CSF1R) signaling is crucial for the maintenance and function of various myeloid subsets. CSF1R antagonism was previously shown to mitigate clinical severity in experimental autoimmune encephalomyelitis (EAE). The associated mechanisms are still not well delineated.

METHODS

To assess the effect of CSF1R signaling, we employed the CSF1R antagonist PLX5622 formulated in chow (PLX5622 diet, PD) and its control chow (control diet, CD). We examined the effect of PD in steady state and EAE by analyzing cells isolated from peripheral immune organs and from the CNS via flow cytometry. We determined CNS infiltration sites and assessed the extent of demyelination using immunohistochemistry of cerebella and spinal cords. Transcripts of genes associated with neuroinflammation were also analyzed in these tissues.

RESULTS

In addition to microglial depletion, PD treatment reduced dendritic cells and macrophages in peripheral immune organs, both during steady state and during EAE. Furthermore, CSF1R antagonism modulated numbers and relative frequencies of T effector cells both in the periphery and in the CNS during the early stages of the disease. Classical neurological symptoms were milder in PD compared to CD mice. Interestingly, a subset of PD mice developed atypical EAE symptoms. Unlike previous studies, we observed that the CNS of PD mice was infiltrated by increased numbers of peripheral immune cells compared to that of CD mice. Immunohistochemical analysis showed that CNS infiltrates in PD mice were mainly localized in the cerebellum while in CD mice infiltrates were primarily localized in the spinal cords during the onset of neurological deficits. Accordingly, during the same timepoint, cerebella of PD but not of CD mice had extensive demyelinating lesions, while spinal cords of CD but not of PD mice were heavily demyelinated.

CONCLUSIONS

Our findings suggest that CSF1R activity modulates the cellular composition of immune cells both in the periphery and within the CNS, and affects lesion localization during the early EAE stages.

Exploring causal correlations between inflammatory cytokines and knee osteoarthritis: a two-sample Mendelian randomization

Objectives

Knee osteoarthritis (KOA) and certain inflammatory cytokines (such as interleukin 1 [IL-1] and tumor necrosis factor alpha [TNF-a]) are related; however, the causal relationship remains unclear. Here, we aimed to assess the causal relationship between 41 inflammatory cytokines and KOA using Mendelian randomization (MR).

Methods

Two-sample bidirectional MR was performed using genetic variation data for 41 inflammatory cytokines that were obtained from European Genome-Wide Association Study (GWAS) data (n=8293). KOA-related genetic association data were also obtained from European GWAS data (n=40,3124). Inverse variance weighting (IVW), MR, heterogeneity, sensitivity, and multiple validation analyses were performed.

Results

Granulocyte colony-stimulating factor (G-CSF) or colony-stimulating factor 3 (CSF-3) levels were negatively associated with the risk of developing KOA (OR: 0.93, 95%CI:0.89-0.99, P=0.015). Additionally, macrophage inflammatory protein-1 alpha (MIP-1A/CCL3) was a consequence of KOA (OR: 0.72, 95%CI:0.54-0.97, P=0.032). No causal relationship was evident between other inflammatory cytokines and KOA development.

Conclusion

This study suggests that certain inflammatory cytokines may be associated with KOA etiology. G-CSF exerts an upstream influence on KOA development, whereas MIP-1A (CCL-3) acts as a downstream factor.

Drug Repurposing of ACT001 to Discover Novel Promising Sulfide Prodrugs with Improved Safety and Potent Activity for Neutrophil-Mediated Antifungal Immunotherapy

Neutrophil-mediated immunotherapy is a promising strategy for treating Candida albicans infection due to its potential in dealing with drug-resistant events. Our previous study found that ACT001 exhibited good antifungal immunotherapeutic activity by inhibiting PD-L1 expression in neutrophils, but its strong cytotoxicity and high BBB permeability hindered its antifungal application. To address these deficiencies, a series of novel sulfide derivatives were designed and synthesized based on a slow-release prodrug strategy. Among these derivatives, compound 16 exhibited stronger inhibition of PD-L1 expression, less cytotoxicity to neutrophils, and lower BBB permeability than ACT001. Compound 16 also significantly enhanced neutrophil-mediated antifungal immunity in C. albicans infected mice, with acceptable pharmacokinetic properties and good oral safety. Moreover, pharmacological mechanism studies demonstrated that ACT001 and compound 16 reduced PD-L1 expression in neutrophils by directly targeting STAT3. Briefly, this study provided a novel prototype compound 16 which exhibited great potential in neutrophil-mediated antifungal immunotherapy.

Neutrophil hitchhiking: Riding the drug delivery wave to treat diseases

Neutrophils are a crucial component of the innate immune system and play a pivotal role in various physiological processes. From a physical perspective, hitchhiking is considered a phenomenon of efficient transportation. The combination of neutrophils and hitchhikers has given rise to effective delivery systems both in vivo and in vitro, thus neutrophils hitchhiking become a novel approach to disease treatment. This article provides an overview of the innovative and feasible application of neutrophils as drug carriers. It explores the mechanisms underlying neutrophil function, elucidates the mechanism of drug delivery mediated by neutrophil-hitchhiking, and discusses the potential applications of this strategy in the treatment of cancer, immune diseases, inflammatory diseases, and other medical conditions.

CD200Rhigh neutrophils with dysfunctional autophagy establish systemic immunosuppression by increasing regulatory T cells

Distinct neutrophil populations arise during certain pathological conditions. The generation of dysfunctional neutrophils during sepsis and their contribution to septicemia-related systemic immune suppression remain unclear. In this study, using an experimental sepsis model that features immunosuppression, we identified a novel population of pathogenic CD200Rhigh neutrophils that are generated during the initial stages of sepsis and contribute to systemic immune suppression by enhancing regulatory T (Treg) cells. Compared to their CD200Rlow counterparts, sepsis-generated CD200Rhigh neutrophils exhibit impaired autophagy and dysfunction, with reduced chemotactic migration, superoxide anion production, and TNF-α production. Increased soluble CD200 blocks autophagy and neutrophil maturation in the bone marrow during experimental sepsis, and recombinant CD200 treatment in vitro can induce neutrophil dysfunction similar to that observed in CD200Rhigh neutrophils. The administration of an α-CD200R antibody effectively reversed neutrophil dysfunction by enhancing autophagy and protecting against a secondary infection challenge, leading to increased survival. Transcriptome analysis revealed that CD200Rhigh neutrophils expressed high levels of Igf1, which elicits the generation of Treg cells, while the administration of an α-CD200R antibody inhibited Treg cell generation in a secondary infection model. Taken together, our findings revealed a novel CD200Rhigh neutrophil population that mediates the pathogenesis of sepsis-induced systemic immunosuppression by generating Treg cells.

Kinetics of Inflammatory Mediators in the Immune Response to Burn Injury: Systematic Review and Meta-Analysis of Animal Studies

Burns are often accompanied by a dysfunctional immune response, which can lead to systemic inflammation, shock, and excessive scarring. The objective of this study was to provide insight into inflammatory pathways associated with burn-related complications. Because detailed information on the various inflammatory mediators is scattered over individual studies, we systematically reviewed animal experimental data for all reported inflammatory mediators. Meta-analyses of 352 studies revealed a strong increase in cytokines, chemokines, and growth factors, particularly 19 mediators in blood and 12 in burn tissue. Temporal kinetics showed long-lasting surges of proinflammatory cytokines in blood and burn tissue. Significant time-dependent effects were seen for IL-1β, IL-6, TGF-β1, and CCL2. The response of anti-inflammatory mediators was limited. Burn technique had a profound impact on systemic response levels. Large burn size and scalds further increased systemic, but not local inflammation. Animal characteristics greatly affected inflammation, for example, IL-1β, IL-6, and TNF-α levels were highest in young, male rats. Time-dependent effects and dissimilarities in response demonstrate the importance of appropriate study design. Collectively, this review presents a general overview of the burn-induced immune response exposing inflammatory pathways that could be targeted through immunotherapy for burn patients and provides guidance for experimental set-ups to advance burn research.

Whole blood transcriptomics reveals granulocyte colony-stimulating factor as a mediator of cardiopulmonary bypass-induced systemic inflammatory response syndrome

Objectives

Systemic inflammatory response syndrome (SIRS) is a frequent complication of cardiopulmonary bypass (CPB). SIRS is associated with significant morbidity and mortality, but its pathogenesis remains incompletely understood, and as a result, biomarkers are lacking and treatment remains expectant and supportive. This study aimed to understand the pathophysiological mechanisms driving SIRS induced by CPB and identify novel therapeutic targets that might reduce systemic inflammation and improve patient outcomes.

Methods

Twenty-one patients undergoing cardiac surgery and CPB were recruited, and blood was sampled before, during and after surgery. SIRS was defined using the American College of Chest Physicians/Society of Critical Care Medicine criteria. We performed immune cell profiling and whole blood transcriptomics and measured individual mediators in plasma/serum to characterise SIRS induced by CPB.

Results

Nineteen patients fulfilled criteria for SIRS, with a mean duration of 2.7 days. Neutrophil numbers rose rapidly with CPB and remained elevated for at least 48 h afterwards. Transcriptional signatures associated with neutrophil activation and degranulation were enriched during CPB. We identified a network of cytokines governing these transcriptional changes, including granulocyte colony-stimulating factor (G-CSF), a regulator of neutrophil production and function.

Conclusions

We identified neutrophils and G-CSF as major regulators of CPB-induced systemic inflammation. Short-term targeting of G-CSF could provide a novel therapeutic strategy to limit neutrophil-mediated inflammation and tissue damage in SIRS induced by CPB.

Isolation and characterization of a pangolin-borne HKU4-related coronavirus that potentially infects human-DPP4-transgenic mice

We recently detected a HKU4-related coronavirus in subgenus Merbecovirus (named pangolin-CoV-HKU4-P251T) from a Malayan pangolin1. Here we report isolation and characterization of pangolin-CoV-HKU4-P251T, the genome sequence of which is closest to that of a coronavirus from the greater bamboo bat (Tylonycteris robustula) in Yunnan Province, China, with a 94.3% nucleotide identity. Pangolin-CoV-HKU4-P251T is able to infect human cell lines, and replicates more efficiently in cells that express human-dipeptidyl-peptidase-4 (hDPP4)-expressing and pangolin-DPP4-expressing cells than in bat-DPP4-expressing cells. After intranasal inoculation with pangolin-CoV-HKU4-P251, hDPP4-transgenic female mice are likely infected, showing persistent viral RNA copy numbers in the lungs. Progressive interstitial pneumonia developed in the infected mice, characterized by the accumulation of macrophages, and increase of antiviral cytokines, proinflammatory cytokines, and chemokines in lung tissues. These findings suggest that the pangolin-borne HKU4-related coronavirus has a potential for emerging as a human pathogen by using hDPP4.

G-CSF reshapes the cytosolic PCNA scaffold and modulates glycolysis in neutrophils

Cytosolic proliferating cell nuclear antigen (PCNA) is involved in neutrophil survival and function, in which it acts as a scaffold and associates with proteins involved in apoptosis, NADPH oxidase activation, cytoskeletal dynamics, and metabolism. While the PCNA interactome has been characterized in neutrophils under homeostatic conditions, less is known about neutrophil PCNA in pathophysiological contexts. Granulocyte colony-stimulating factor (G-CSF) is a cytokine produced in response to inflammatory stimuli that regulates many aspects of neutrophil biology. Here, we used isolated normal-density neutrophils from G-CSF-treated haemopoietic stem cell donors (GDs) as a model to understand the role of PCNA during inflammation. Proteomic analysis of the neutrophil cytosol revealed significant differences between GDs and healthy donors (HDs). PCNA was one of the most upregulated proteins in GDs, and the PCNA interactome was significantly different in GDs compared with HDs. Importantly, while PCNA associated with almost all enzymes involved in glycolysis in HDs, these associations were decreased in GDs. Functionally, neutrophils from GDs had a significant increase in glycolysis compared with HDs. Using p21 competitor peptides, we showed that PCNA negatively regulates neutrophil glycolysis in HDs but had no effect on GD neutrophils. These data demonstrate that G-CSF alters the PCNA scaffold, affecting interactions with key glycolytic enzymes, and thus regulates glycolysis, the main energy pathway utilized by neutrophils. By this selective control of glycolysis, PCNA can organize neutrophils functionality in parallel with other PCNA mechanisms of prolonged survival. PCNA may therefore be instrumental in the reprogramming that neutrophils undergo in inflammatory or tumoral settings.

Associations of the circulating levels of cytokines with risk of ankylosing spondylitis: a Mendelian randomization study

Background

Observational studies have shown that changes in circulating cytokine/growth factor levels occur throughout the initiation and progression of ankylosing spondylitis (AS), yet whether they are etiologic or downstream effects remains unclear. In this study, we performed a summarized-level bidirectional Mendelian randomization (MR) analysis to shed light on the causal relationship between the two.

Methods

Genetic instrumental-variables (IVs) associated with circulating cytokine/growth factor levels were derived from a genome-wide association study (GWAS) of 8,293 European individuals, whereas summary data for the AS were obtained from a FinnGen GWAS of 166,144 participants. We used the inverse-variance-weighted (IVW) method as the main analysis for causal inference. Furthermore, several sensitivity analyses (MR-Egger, weighted median, MR-PRESSO and Cochran's Q test) were utilized to examine the robustness of the results. Finally, reverse MR analysis was performed to assess reverse causality between AS and circulating cytokine/growth factor levels.

Results

After Bonferroni correction, circulating levels of Cutaneous T-cell attracting (CTACK) and Monocyte specific chemokine 3 (MCP-3) were positively associated with a higher risk of AS (odds ratio [OR]: 1.224, 95% confidence interval [95% Cl]: 1.022 ~ 1.468, P = 0.028; OR: 1.250, 95% Cl: 1.016 ~ 1.539, P = 0.035). In addition, elevated circulating levels of Basic fibroblast growth factor (FGF-basic), Granulocyte colony-stimulating factor (G-CSF) and MCP-3 was considered a consequence of AS disease (β = 0.023, P = 0.017; β = 0.017, P = 0.025; β = 0.053, P = 0.025). The results of the sensitivity analysis were generally consistent.

Conclusion

The present study supplies genetic evidence for the relationship between circulating cytokine levels and AS. Targeted interventions of specific cytokines may help to reduce the risk of AS initiation and progression.

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.

Neutrophil diversity and plasticity: Implications for organ transplantation

Neutrophils, as the first defenders against external microbes and stimuli, are highly active and finely regulated innate immune cells. Emerging evidence has challenged the conventional dogma that neutrophils are a homogeneous population with a short lifespan that promotes tissue damage. Recent findings on neutrophil diversity and plasticity in homeostatic and disease states have centered on neutrophils in the circulation. In contrast, a comprehensive understanding of tissue-specialized neutrophils in health and disease is still lacking. This article will first discuss how multiomics advances have contributed to our understanding of neutrophil heterogeneity and diversification in resting and pathological settings. This discussion will be followed by a focus on the heterogeneity and role of neutrophils in solid organ transplantation and how neutrophils may contribute to transplant-related complications. The goal of this article is to provide an overview of the research on the involvement of neutrophils in transplantation, with the aim that this may draw attention to an underappreciated area of neutrophil research.

Maternal Obesity and Kawasaki Disease-like Vasculitis: A New Perspective on Cardiovascular Injury and Inflammatory Response in Offspring Male Mice

Maternal obesity affects the risk of cardiovascular disease and inflammatory response in offspring. However, the impact of maternal obesity on offspring with Kawasaki disease (KD), the leading cause of childhood acquired heart disease, is still an understudied area. This study aimed to elucidate the impact of maternal obesity on offspring in KD-like vasculitis and the underlying mechanisms. Offspring of obese female mice and normal diet dams were randomly divided into two subgroups. The pups were injected intraperitoneally with either Candida albicans water-soluble fraction (CAWS) or phosphate buffered saline (PBS) to establish the obesity (OB)-CAWS group, OB group, wild type (WT)-CAWS group, and WT group. Their weight was monitored during the study. After four weeks, echocardiography was applied to obtain the alternation of cardiac structures. Mouse cytokine panel, Hematoxylin-Eosin (HE) staining, western blot, and real-time qPCR were used to study the pathological changes and protein and RNA expression alternations. Based on the study of pathology, serology and molecular biology, maternal obesity lead to more severe vasculitis and induced altered cardiac structure in the offspring mice and promoted the expression of pro-inflammatory cytokines through activating the NF-κB signaling pathway. Maternal obesity aggravated the inflammatory response of offspring mice in KD-like vasculitis.

Neutrophils: a subgroup of neglected immune cells in ALS

Amyotrophic lateral sclerosis (ALS) is a chronic, progressive neurodegenerative disease characterized by the loss of motor neurons. Dysregulated peripheral immunity has been identified as a hallmark of ALS. Neutrophils, as the front-line responders of innate immunity, contribute to host defense through pathogen clearance. However, they can concurrently play a detrimental role in chronic inflammation. With the unveiling of novel functions of neutrophils in neurodegenerative diseases, it becomes essential to review our current understanding of neutrophils and to recognize the gap in our knowledge about their role in ALS. Thus, a detailed comprehension of the biological processes underlying neutrophil-induced pathogenesis in ALS may assist in identifying potential cell-based therapeutic strategies to delay disease progression.

Post-Transplant Administration of G-CSF Impedes Engraftment of Gene Edited Human Hematopoietic Stem Cells by Exacerbating the p53-Mediated DNA Damage Response

Granulocyte colony stimulating factor (G-CSF) is commonly used as adjunct treatment to hasten recovery from neutropenia following chemotherapy and autologous transplantation of hematopoietic stem and progenitor cells (HSPCs) for malignant disorders. However, the utility of G-CSF administration after ex vivo gene therapy procedures targeting human HSPCs has not been thoroughly evaluated. Here, we provide evidence that post-transplant administration of G-CSF impedes engraftment of CRISPR-Cas9 gene edited human HSPCs in xenograft models. G-CSF acts by exacerbating the p53-mediated DNA damage response triggered by Cas9- mediated DNA double-stranded breaks. Transient p53 inhibition in culture attenuates the negative impact of G-CSF on gene edited HSPC function. In contrast, post-transplant administration of G-CSF does not impair the repopulating properties of unmanipulated human HSPCs or HSPCs genetically engineered by transduction with lentiviral vectors. The potential for post-transplant G-CSF administration to aggravate HSPC toxicity associated with CRISPR-Cas9 gene editing should be considered in the design of ex vivo autologous HSPC gene editing clinical trials.

NADPH oxidase 2 limits amplification of IL-1β-G-CSF axis and an immature neutrophil subset in murine lung inflammation

The leukocyte NADPH oxidase 2 (NOX2) regulates inflammation independent of its antimicrobial activity. Inherited defects in NOX2 lead to chronic granulomatous disease (CGD), associated with recurrent bacterial and fungal infections, often with excessive neutrophilic inflammation that results in significant inflammatory burden and tissue damage. We previously showed that excessive leukotriene B4 (LTB4) production by NOX2-deficient mouse neutrophils was a key driver of elevated lung neutrophil infiltration in the initial response to pulmonary challenge with the model fungal particle zymosan. We now identify interleukin-1β (IL-1β) and downstream granulocyte colony-stimulating factor (G-CSF) as critical amplifying signals that augment and sustain neutrophil accrual in CGD mice. Neutrophils, delivered into the lung via LTB4, were the primary source of IL-1β within the airways, and their increased numbers in CGD lungs led to significantly elevated local and plasma G-CSF. Elevated G-CSF simultaneously promoted increased granulopoiesis and mobilized the release of higher numbers of an immature CD101- neutrophil subset from the marrow, which trafficked to the lung and acquired a significantly more proinflammatory transcriptome in CGD mice compared with wild-type mice. Thus, neutrophil-produced IL-1β and downstream G-CSF act sequentially but nonredundantly with LTB4 to deploy neutrophils and amplify inflammation in CGD mice after inhalation of zymosan. NOX2 plays a critical role in dampening multiple components of a feed-forward pipeline for neutrophil recruitment, and these findings highlight NOX2 as a key regulator of neutrophil number, subsets, and function at inflamed sites.

A congenital CSF3R mutation in chronic neutropenia reveals a vital role for a cytokine receptor extracellular hinge motif in the response to granulocyte colony-stimulating factor

We describe a patient with congenital neutropenia (CN) with a homozygous germline mutation in the colony-stimulating factor 3 receptor gene (CSF3R). The patient's bone marrow shows lagging neutrophil development with subtle left shift and unresponsiveness to CSF3 in in vitro colony assays. This patient illustrates that the di-proline hinge motif in the extracellular cytokine receptor homology domain of CSF3R is critical for adequate neutrophil production, but dispensable for in vivo terminal neutrophil maturation. This report underscores that CN patients with inherited CSF3R mutations should be marked as a separate clinical entity, characterized by a failure to respond to CSF3.

Multi-Omics Profiling in PGM3 and STAT3 Deficiencies: A Tale of Two Patients

Hyper-IgE Syndrome (HIES) is a heterogeneous group of primary immune-deficiency disorders characterized by elevated levels of IgE, eczema, and recurrent skin and lung infections. HIES that is autosomally dominant in the signal transducer and activator of transcription 3 (STAT3), and autosomal recessive mutations in phosphoglucomutase 3 (PGM3) have been reported in humans. An early diagnosis, based on clinical suspicion and immunological assessments, is challenging. Patients' metabolomics, proteomics, and cytokine profiles were compared to DOCK 8-deficient and atopic dermatitis patients. The PGM3 metabolomics profile identified significant dysregulation in hypotaurine, hypoxanthine, uridine, and ribothymidine. The eight proteins involved include bifunctional arginine demethylase and lysyl hydroxylase (JMJD1B), type 1 protein phosphatase inhibitor 4 (PPI 4), and platelet factor 4 which aligned with an increased level of the cytokine GCSF. Patients with STAT3 deficiency, on the other hand, showed significant dysregulation in eight metabolites, including an increase in protocatechuic acid, seven proteins including ceruloplasmin, and a plasma protease C1 inhibitor, in addition to cytokine VEGF being dysregulated. Using multi-omics profiling, we identified the dysregulation of endothelial growth factor (EGFR) and tumor necrosis factor (TNF) signaling pathways in PGM3 and STAT3 patients, respectively. Our findings may serve as a stepping stone for larger prospective HIES clinical cohorts to validate their future use as biomarkers.

Evolution of developmental and comparative immunology in poultry: The regulators and the regulated

Avian has a unique immune system that evolved in response to environmental pressures in all aspects of innate and adaptive immune responses, including localized and circulating lymphocytes, diversity of immunoglobulin repertoire, and various cytokines and chemokines. All of these attributes make birds an indispensable vertebrate model for studying the fundamental immunological concepts and comparative immunology. However, research on the immune system in birds lags far behind that of humans, mice, and other agricultural animal species, and limited immune tools have hindered the adequate application of birds as disease models for mammalian systems. An in-depth understanding of the avian immune system relies on the detailed studies of various regulated and regulatory mediators, such as cell surface antigens, cytokines, and chemokines. Here, we review current knowledge centered on the roles of avian cell surface antigens, cytokines, chemokines, and beyond. Moreover, we provide an update on recent progress in this rapidly developing field of study with respect to the availability of immune reagents that will facilitate the study of regulatory and regulated components of poultry immunity. The new information on avian immunity and available immune tools will benefit avian researchers and evolutionary biologists in conducting fundamental and applied research.

Advances in cell membrane-coated nanoparticles and their applications for bone therapy

Due to the specific structure of natural bone, most of the therapeutics are incapable to be delivered into the targeted site with effective concentrations. Nanotechnology has provided a good way to improve this issue, cell membrane mimetic nanoparticles (NPs) have been emerging as an ideal nanomaterial which integrates the advantages of natural cell membranes with synthetic NPs to significantly improve the biocompatibility as well as achieving long-lasting circulation and targeted delivery. In addition, functionalized modifications of the cell membrane facilitate more precise targeting and therapy. Here, an overview of the preparation of cell membrane-coated NPs and the properties of cell membranes from different cell sources has been given to expatiate their function and potential applications. Strategies for functionalized modification of cell membranes are also briefly described. The application of cell membrane-coated NPs for bone therapy is then presented according to the function of cell membranes. Moreover, the prospects and challenges of cell membrane-coated NPs for translational medicine have also been discussed.

CD98 defines a metabolically flexible, proinflammatory subset of low-density neutrophils in systemic lupus erythematosus

BACKGROUND

Low-density neutrophils (LDN) are a distinct subset of neutrophils rarely detected in healthy people but appear in the blood of patients with autoimmune diseases, including systemic lupus erythematosus (SLE), and are mobilised in response to granulocyte colony-stimulating factor (G-CSF). The aim of this study was to identify novel mechanisms responsible for the pathogenic capacity of LDN in SLE.

METHODS

Neutrophils were isolated from donors treated with G-CSF, and whole-cell proteomic analysis was performed on LDN and normal-density neutrophils.

RESULTS

CD98 is significantly upregulated in LDN from G-CSF donors and defines a subset of LDN within the blood of SLE patients. CD98 is a transmembrane protein that dimerises with L-type amino acid transporters. We show that CD98 is responsible for the increased bioenergetic capacity of LDN. CD98 on LDN mediates the uptake of essential amino acids that are used by mitochondria to produce adenosine triphosphate, especially in the absence of glucose. Inhibition of CD98 reduces the metabolic flexibility of this population, which may limit their pathogenic capacity. CD98+ LDN produce more proinflammatory cytokines and chemokines than their normal density counterparts and are resistant to apoptosis, which may also contribute to tissue inflammation and end organ damage in SLE.

CONCLUSIONS

CD98 provides a phenotypic marker for LDN that facilitates identification of this population without density-gradient separation and represents a novel therapeutic target to limit its pathogenic capacity.

Inflammatory checkpoints in amyotrophic lateral sclerosis: From biomarkers to therapeutic targets

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive motor neuron damage. Due to the complexity of the ALS, so far the etiology and underlying pathogenesis of sporadic ALS are not completely understood. Recently, many studies have emphasized the role of inflammatory networks, which are comprised of various inflammatory molecules and proteins in the pathogenesis of ALS. Inflammatory molecules and proteins may be used as independent predictors of patient survival and might be used in patient stratification and in evaluating the therapeutic response in clinical trials. This review article describes the latest advances in various inflammatory markers in ALS and its animal models. In particular, this review discusses the role of inflammatory molecule markers in the pathogenesis of the disease and their relationship with clinical parameters. We also highlight the advantages and disadvantages of applying inflammatory markers in clinical manifestations, animal studies, and drug clinical trials. Further, we summarize the potential application of some inflammatory biomarkers as new therapeutic targets and therapeutic strategies, which would perhaps expand the therapeutic interventions for ALS.

Inhibition of IRAK1 Is an Effective Therapy for Autoimmune Hypophysitis in Mice

Autoimmune hypophysitis (AH) is an autoimmune disease of the pituitary for which the pathogenesis is incompletely known. AH is often treated with corticosteroids; however, steroids may lead to considerable side effects. Using a mouse model of AH (experimental autoimmune hypophysitis, EAH), we show that interleukin-1 receptor-associated kinase 1 (IRAK1) is upregulated in the pituitaries of mice that developed EAH. We identified rosoxacin as a specific inhibitor for IRAK1 and found it could treat EAH. Rosoxacin treatment at an early stage (day 0-13) slightly reduced disease severity, whereas treatment at a later stage (day 14-27) significantly suppressed EAH. Further investigation indicated rosoxacin reduced production of autoantigen-specific antibodies. Rosoxacin downregulated production of cytokines and chemokines that may dampen T cell differentiation or recruitment to the pituitary. Finally, rosoxacin downregulated class II major histocompatibility complex expression on antigen-presenting cells that may lead to impaired activation of autoantigen-specific T cells. These data suggest that IRAK1 may play a pathogenic role in AH and that rosoxacin may be an effective drug for AH and other inflammatory diseases involving IRAK1 dysregulation.

PD-L1 negatively regulates antifungal immunity by inhibiting neutrophil release from bone marrow

Programmed death ligand 1 (PD-L1) has been shown to be inducibly expressed on neutrophils to suppress host immunity during polymicrobial sepsis, virus and parasite infections. However, the role of PD-L1 on neutrophil-mediated antifungal immunity remains wholly unknown. Here, we show that the expression of PD-L1 on murine and human neutrophils was upregulated upon the engagement of C-type lectin receptor Dectin-1 with its ligand β-glucans, exposed on fungal pathogen Candida albicans yeast. Moreover, β-glucan stimulation induced PD-L1 translocation into nucleus to regulate the production of chemokines CXCL1 and CXCL2, which control neutrophil mobilization. Importantly, C. albicans infection-induced expression of PD-L1 leads to neutrophil accumulation in bone marrow, through mediating their autocrine secretion of CXCL1/2. Furthermore, neutrophil-specific deficiency of PD-L1 impaired CXCL1/2 secretion, which promoted neutrophil migration from bone marrow into the peripheral circulation, thereby conferring host resistance to C. albicans infection. Finally, either PD-L1 blockade or pharmacological inhibition of PD-L1 expression significantly increased neutrophil release from bone marrow to enhance host antifungal immunity. Our data together indicate that activation of Dectin-1/PD-L1 cascade by β-glucans inhibits neutrophil release from bone marrow reserve, contributing to the negative regulation of antifungal innate immunity, which functions as a potent immunotherapeutic target against life-threatening fungi infections.

Neutrophils in pancreatic cancer: Potential therapeutic targets

Pancreatic cancer is a digestive system malignancy and poses a high mortality worldwide. Traditionally, neutrophils have been thought to play a role in acute inflammation. In contrast, their importance during tumor diseases has been less well studied. Generally, neutrophils are recruited into the tumor microenvironment and exert inflammation and tumor-promoting effects. As an essential part of the tumor microenvironment, neutrophils play diverse roles in pancreatic cancer, such as angiogenesis, progression, metastasis and immunosuppression. Additionally, neutrophils can be a new potential therapeutic target in cancer. Inhibitors of cytokines, chemokines and neutrophil extracellular traps can exert antitumor effects. In this review, we describe the role of neutrophils in the development and progression of pancreatic cancer, discuss their potential as therapeutic targets, and aim to provide ideas for improving the prognosis of patients with this malignant tumor disease.

The Role of Growth Factors in the Pathogenesis of Dengue: A Scoping Review

Growth factors (GFs) have a role in tissue repair and in the modulation of the expression of inflammatory cells in damage caused by pathogens. This study aims to systematize the evidence on the role of GFs in the pathogenesis of dengue. This scoping review considered all published peer-reviewed studies in the MEDLINE and Embase databases. Ultimately, 58 studies that analyzed GFs in dengue patients, published between 1998 and 2021, were included. DENV-2 infection and secondary infection were more frequent in the patients studied. ELISA and multiplex immunoassay (Luminex) were the most used measurement techniques. Increased levels of vascular endothelial growth factor, granulocyte-macrophage colony-stimulating factor, granulocyte colony-stimulating factor, transforming growth factor beta, and hepatocyte growth factor as well as reduced levels of platelet-derived growth factor and epidermal growth factor were observed in severe dengue in most studies. Vascular endothelial growth factor and hepatocyte growth factor were identified as biomarkers of severity. In addition, there is evidence that the dengue virus can use the growth factor pathway to facilitate its entry into the cell and promote its viral replication. The use of tyrosine kinase inhibitors is an alternative treatment for dengue that is being studied.