Evaluation of the effect of GM-CSF blocking on the phenotype and function of human monocytes

Granulocyte-Macrophage Colony-Stimulating Factor in Combination With Chemoradiation for Recurrent or Metastatic Cervical Cancer

Recurrent or metastatic cervical cancer carries a bleak prognosis and presents a formidable challenge in terms of treatment. Granulocyte-macrophage colony-stimulating factor (GM-CSF) increases the body's immune response by enhancing antigen presentation, which has been rarely reported in recurrent or metastatic cervical cancer. A 44-year-old woman presented to the hospital with vaginal bleeding four years after radical hysterectomy for stage IB2 squamous cell carcinoma (SCC) of the cervix (grade II-III). Gynecological examination and imaging revealed a vaginal mass, and the biopsy confirmed the recurrence of grade III SCC. The patient was treated with chemoradiation (CRT) combined with immunoadjuvant GM-CSF and achieved complete remission and a progression-free survival of two years.

Immunophenotype associated with high sustained antibody titers against enzyme replacement therapy in infantile-onset Pompe disease

Introduction

The efficacy of enzyme replacement therapy (ERT) with alglucosidase alfa for infantile-onset Pompe disease (IOPD) is limited in some patients due to the development of high and sustained antibody titers (HSAT; ≥12,800).

Methods

We carried out detailed immunophenotyping of IOPD patients (n=40), including analysis of circulating cell populations by flow cytometry and plasma cytokines by multiplex array, to determine whether patients with HSAT have unique immunological characteristics compared to those with low titers (LT; <12,800).

Results

Compared to patients with LT, patients who develop HSAT were skewed toward a type 2 immune profile, with an increased frequency of Th2 cells that was positively correlated with levels of Th2 (IL-4, IL-5, IL-13) and pro-inflammatory (IL-6, TNF-α, MIP-1α, MIP-1β) cytokines. B cells were increased in HSAT patients with a decreased fraction of unswitched memory B cells. Plasma GM-CSF concentrations were lower on average in HSAT patients, while CXCL11 was elevated. Finally, using principal components analysis, we derived an HSAT Signature Score that successfully stratified patients according to their antibody titers.

Discussion

The immune profiles revealed in this study not only identify potential biomarkers of patients that developed HSAT but also provide insights into the pathophysiology of HSAT that will ultimately lead to improved immunotherapy strategies.

Single-cell profiling and zebrafish avatars reveal LGALS1 as immunomodulating target in glioblastoma

Glioblastoma (GBM) remains the most malignant primary brain tumor, with a median survival rarely exceeding 2 years. Tumor heterogeneity and an immunosuppressive microenvironment are key factors contributing to the poor response rates of current therapeutic approaches. GBM-associated macrophages (GAMs) often exhibit immunosuppressive features that promote tumor progression. However, their dynamic interactions with GBM tumor cells remain poorly understood. Here, we used patient-derived GBM stem cell cultures and combined single-cell RNA sequencing of GAM-GBM co-cultures and real-time in vivo monitoring of GAM-GBM interactions in orthotopic zebrafish xenograft models to provide insight into the cellular, molecular, and spatial heterogeneity. Our analyses revealed substantial heterogeneity across GBM patients in GBM-induced GAM polarization and the ability to attract and activate GAMs-features that correlated with patient survival. Differential gene expression analysis, immunohistochemistry on original tumor samples, and knock-out experiments in zebrafish subsequently identified LGALS1 as a primary regulator of immunosuppression. Overall, our work highlights that GAM-GBM interactions can be studied in a clinically relevant way using co-cultures and avatar models, while offering new opportunities to identify promising immune-modulating targets.

The role of miRNAs in multiple sclerosis pathogenesis, diagnosis, and therapeutic resistance

In recent years, microRNAs (miRNAs) have gained increased attention from researchers around the globe. Although it is twenty nucleotides long, it can modulate several gene targets simultaneously. Their mal expression is a signature of various pathologies, and they provide the foundation to elucidate the molecular mechanisms of each pathology. Among the debilitating central nervous system (CNS) disorders with a growing prevalence globally is the multiple sclerosis (MS). Moreover, the diagnosis of MS is challenging due to the lack of disease-specific biomarkers, and the diagnosis mainly depends on ruling out other disabilities. MS could adversely affect patients' lives through its progression, and only symptomatic treatments are available as therapeutic options, but an exact cure is yet unavailable. Consequently, this review hopes to further the study of the biological features of miRNAs in MS and explore their potential as a therapeutic target.

Recombinant GM-CSF enhances the bactericidal ability of PMNs by increasing intracellular IL-1β and improves the prognosis of secondary Pseudomonas aeruginosa pneumonia in sepsis

This study tested the hypothesis that recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF) enhances polymorphonuclear neutrophils (PMNs) via interleukin (IL)-1β to improve the prognosis of secondary infection in sepsis. The latter stage of sepsis is prone to induce immunosuppression, resulting in secondary fatal infections. Recombinant GM-CSF has become a way for sepsis-induced immunosuppression due to its immunomodulatory effect. However, the functional impact of GM-CSF on PMNs in sepsis remains obscure. This study aimed to study the role of recombinant GM-CSF on the bactericidal ability of PMNs in septic mice, assessing its effect on the prognosis of secondary pneumonia, and explore the mechanism of recombinant GM-CSF by intervening PMNs in patients with sepsis. The C57BL/6J sepsis mouse model was induced by cecal ligation and puncture. Recombinant murine GM-CSF (rmGM-CSF) was used in vivo when mice developed immunosuppression, which was characterized by abnormal bactericidal function of PMNs in peripheral blood. rmGM-CSF improved the prognosis of secondary pneumonia and reversed the function of PMNs. PMNs isolated by Percoll from septic patients were treated by recombinant human GM-CSF (rhGM-CSF) in vitro. The expression of CD11b, reactive oxygen species, phagocytosis, and neutrophil extracellular trap release in PMNs were enhanced by rhGM-CSF treatments. Whole-transcriptomic sequencing of mouse PMNs indicated that recombinant GM-CSF increased the expression of Il1b gene in PMNs. Blocking and inhibiting IL-1β release effectively counteracted the enhancing effect of GM-CSF on the bactericidal function of PMNs. rmGM-CSF enhances the bactericidal function of PMNs in vivo and improves the prognosis of secondary pneumonia in septic mice, and recombinant GM-CSF increases IL-1β precursor reserves, which, if stimulated, can rapidly enhance the bactericidal capacity of PMNs.

GM-CSF distinctly impacts human monocytes and macrophages via ERK1/2-dependent pathways

Human monocytes and macrophages are two major myeloid cell subsets with similar and distinct functions in tissue homeostasis and immune responses. GM-CSF plays a fundamental role in myeloid cell differentiation and activation. Hence, we compared the effects of GM-CSF on the expression of several immune mediators by human monocytes and monocyte-derived macrophages obtained from healthy donors. We report that GM-CSF similarly elevated the expression of CD80 and ICAM-1 and reduced HLA-DR levels on both myeloid cell subsets. However, GM-CSF increased the percentage of macrophages expressing surface IL-15 but reduced the proportion of monocytes carrying surface IL-15. Moreover, GM-CSF significantly increased the secretion of IL-4, IL-6, TNF, CXCL10, and IL-27 by macrophages while reducing the secretion of IL-4 and CXCL10 by monocytes. We show that GM-CSF triggered ERK1/2, STAT3, STAT5, and SAPK/JNK pathways in both myeloid subsets. Using a pharmacological inhibitor (U0126) preventing ERK phosphorylation, we demonstrated that this pathway was involved in both the GM-CSF-induced increase and decrease of the percentage of IL-15+ macrophages and monocytes, respectively. Moreover, ERK1/2 contributed to GM-CSF-triggered secretion of IL-4, IL-6, TNF, IL-27 and CXCL10 by macrophages. However, the ERK1/2 pathway exhibited different roles in monocytes and macrophages for the GM-CSF-mediated impact on surface makers (CD80, HLA-DR, and ICAM-1). Our data demonstrate that GM-CSF stimulation induces differential responses by human monocytes and monocyte-derived macrophages and that some but not all of these effects are ERK-dependent.

Tetramerization of STAT5 regulates monocyte differentiation and the dextran sulfate sodium-induced colitis in mice

In response to external stimuli during immune responses, monocytes can have multifaceted roles such as pathogen clearance and tissue repair. However, aberrant control of monocyte activation can result in chronic inflammation and subsequent tissue damage. Granulocyte-macrophage colony-stimulating factor (GM-CSF) induces monocyte differentiation into a heterogenous population of monocyte-derived dendritic cells (moDCs) and macrophages. However, the downstream molecular signals that dictate the differentiation of monocytes under pathological conditions is incompletely understood. We report here that the GM-CSF-induced STAT5 tetramerization is a critical determinate of monocyte fate and function. Monocytes require STAT5 tetramers to differentiate into moDCs. Conversely, the absence of STAT5 tetramers results in a switch to a functionally distinct monocyte-derived macrophage population. In the dextran sulfate sodium (DSS) model of colitis, STAT5 tetramer-deficient monocytes exacerbate disease severity. Mechanistically, GM-CSF signaling in STAT5 tetramer-deficient monocytes results in the overexpression of arginase I and a reduction in nitric oxide synthesis following stimulation with lipopolysaccharide. Correspondingly, the inhibition of arginase I activity and sustained supplementation of nitric oxide ameliorates the worsened colitis in STAT5 tetramer-deficient mice. This study suggests that STAT5 tetramers protect against severe intestinal inflammation through the regulation of arginine metabolism.

CHANGES IN SUBSET COMPOSITION AND PHAGOCYTIC ACTIVITY OF MONOCYTES IN CHILDREN WITH INFECTIOUS MONONUCLEOSIS UNDER EXPOSURE TO GM-CSF IN VITRO

The aim of the study was to investigate the features of changes in the subset composition of monocytes and their phagocytic activity in children with infectious mononucleosis (IM) under the influence of granulocyte-macrophage colony-stimulating factor (GM-CSF) in vitro. We examined 84 children aged 3 to 11 years with Epstein-Barr virus (EBV) infection. EBV infection was diagnosed on the basis of clinical signs of IM, a positive test for EBV DNA in blood lymphocytes and results of ELISA tests (EBV-VCAIgM (+), EBV-EA-DIgG (+)). The control group consisted of 40 practically healthy children of the same age range. Monocytes were obtained by the standard method of adhesion to plastic from mononuclear cells isolated from heparinized venous blood by density gradient centrifugation. The isolated monocytes were divided into two samples: control (without GM-CSF) and experimental (50 ng of GM-CSF per 1 ml of cell suspension). The subset composition and phagocytic activity of monocytes in both samples were determined by flow cytometry after incubation for 1 hour at 37C in a CO2-incubator. It was found that in children against the background of the development of IM, the subpopulation composition of monocytes in the blood changes and their phagocytic activity is impaired. It was found that the subset composition and phagocytic activity of the blood monocytes changed in children against the background of the development of IM. Changes in the subset composition of monocytes against the background of acute IM did not depend on the age group of children (3-6 and 7-11 years) and were characterized by an increase in the number of pro-inflammatory (intermediate) monocytes and a decrease in the content of anti-inflammatory (non-classical) monocytes. Features of violation of the phagocytic activity of the monocytes in children with IM depended on age. The phagocytic activity of all three subsets of the monocytes was reduced in children with IM 3-6 years old while children with IM 7-11 years old had reduced phagocytic activity only of intermediate and non-classical monocytes. The effect of GM-CSF in vitro on monocytes in patients with IM, regardless of the age of children, led to a significant increase in the level of anti-inflammatory monocytes while the phagocytic activity of cells changed less. An increase in the phagocytic number for classical monocytes after incubation with GM-CSF in vitro was noted in children with IM at the age of 3-6 years while the phagocytic index of this fraction of monocytes remained unchanged. The level of the phagocytic index increased only in classical monocytes of children with IM aged 7-11 years. The presented results determine the scientific and clinical value of studying the mechanisms of the effect of GM-CSF on cells of the immune system and prove that this cytokine can be used in a new immunotherapeutic strategy for the treatment of IM.

Low-Dose Lipopolysaccharide Protects from Lethal Paramyxovirus Infection in a Macrophage- and TLR4-Dependent Process

Respiratory diseases are a major public health burden and a leading cause of death and disability in the world. Understanding antiviral immune responses is crucial to alleviate morbidity and mortality associated with these respiratory viral infections. Previous data from human and animal studies suggested that pre-existing atopy may provide some protection against severe disease from a respiratory viral infection. However, the mechanism(s) of protection is not understood. Low-dose LPS has been shown to drive an atopic phenotype in mice. In addition, LPS has been shown in vitro to have an antiviral effect. We examined the effect of LPS treatment on mortality to the murine parainfluenza virus Sendai virus. Low-dose LPS treatment 24 h before inoculation with a normally lethal dose of Sendai virus greatly reduced death. This protection was associated with a reduced viral titer and reduced inflammatory cytokine production in the airways. The administration of LPS was associated with a marked increase in lung neutrophils and macrophages. Depletion of neutrophils failed to reverse the protective effect of LPS; however, depletion of macrophages reversed the protective effect of LPS. Further, we demonstrate that the protective effect of LPS depends on type I IFN and TLR4-MyD88 signaling. Together, these studies demonstrate pretreatment with low-dose LPS provides a survival advantage against a severe respiratory viral infection through a macrophage-, TLR4-, and MyD88-dependent pathway.

Understanding the development of Th2 cell-driven allergic airway disease in early life

Allergic diseases, including atopic dermatitis, allergic rhinitis, asthma, and food allergy, are caused by abnormal responses to relatively harmless foreign proteins called allergens found in pollen, fungal spores, house dust mites (HDM), animal dander, or certain foods. In particular, the activation of allergen-specific helper T cells towards a type 2 (Th2) phenotype during the first encounters with the allergen, also known as the sensitization phase, is the leading cause of the subsequent development of allergic disease. Infants and children are especially prone to developing Th2 cell responses after initial contact with allergens. But in addition, the rates of allergic sensitization and the development of allergic diseases among children are increasing in the industrialized world and have been associated with living in urban settings. Particularly for respiratory allergies, greater susceptibility to developing allergic Th2 cell responses has been shown in children living in urban environments containing low levels of microbial contaminants, principally bacterial endotoxins [lipopolysaccharide (LPS)], in the causative aeroallergens. This review highlights the current understanding of the factors that balance Th2 cell immunity to environmental allergens, with a particular focus on the determinants that program conventional dendritic cells (cDCs) toward or away from a Th2 stimulatory function. In this context, it discusses transcription factor-guided functional specialization of type-2 cDCs (cDC2s) and how the integration of signals derived from the environment drives this process. In addition, it analyzes observational and mechanistic studies supporting an essential role for innate sensing of microbial-derived products contained in aeroallergens in modulating allergic Th2 cell immune responses. Finally, this review examines whether hyporesponsiveness to microbial stimulation, particularly to LPS, is a risk factor for the induction of Th2 cell responses and allergic sensitization during infancy and early childhood and the potential factors that may affect early-age response to LPS and other environmental microbial components.

Thymoquinone Effect on Monocyte-Derived Macrophages, Cell-Surface Molecule Expression, and Phagocytosis

Macrophages are one of the most important cells in the immune system. They act as links between innate and adaptive immunities. In this study, the aim was to examine thymoquinone effects on the immunological properties of different macrophages. Peripheral blood mononuclear cells were isolated from blood from healthy volunteers by negative selection of monocytes that had been cultured for seven days to differentiate into macrophages. Cells were cultured with or without the presence of thymoquinone (TQ), which was used in two different concentrations (50 μg/mL and 100 μg/mL. Cluster of differentiation 80 (CD80), cluster of differentiation 86 (CD86), and human leukocyte antigen DR isotype (HLA-DR) were measured by flow cytometry, and the secretion of interferon gamma (IFN-γ) and tumour necrosis factor alpha (TNF-α) was measured. Cells were also tested for their E. coli phagocytosis abilities. The data showed that the expression of HLA-DR was significantly higher in cells treated with 100 μL/mL TQ. In addition, IFN-γ concentration increased in the 100 μg/mL TQ-treated cells. The macrophage phagocytosis results showed a significant difference in 50 μg/mL TQ-treated cells compared to the controls. TQ may enhance the immunological properties of macrophages during the early stages of innate immunity by activating phagocytosis ability and by increasing the expression of HLA-DR and the secretion of IFN-γ, which may enhance the antigen-presentation capabilities of macrophages.

Can GCSF-stimulated donor lymphocyte infusions improve outcomes for relapsed disease following allogeneic hematopoietic cell transplantation? A systematic review and meta-analysis

Donor lymphocyte infusions (DLI) can produce graft-versus tumor effects to treat relapse after allogeneic hematopoietic cell transplantation, however, durable responses remain uncommon. A systematic review and meta-analysis are needed to clarify whether DLI collected after stimulation with granulocyte colony-stimulating factor (GCSF; G-DLI) can improve clinical outcomes. Sixteen studies (4 controlled) involving 585 patients were identified in a systematic search up to 17 September 2020. A meta-analysis demonstrated no significant difference in the risk of all-cause mortality (RR: 0.94, 95% CI 0.52-1.68, p = 0.82; n = 3 studies) or relapse-related mortality (RR: 0.72, 0.44-1.18, p = 0.19; n = 3 studies) between G-DLI and conventional DLI (C-DLI) groups. G-DLI products had similar mean CD3+ cells compared to C-DLI products, but median CD34+ cells/kg were increased. No improvement in disease progression, complete response rates, or risk of developing GVHD was observed with G-DLI, however, greater non-relapse mortality was observed compared to C-DLI. Alternative approaches to enhancing graft-versus-tumor effects are needed.

The immunology of multiple sclerosis

Our incomplete understanding of the causes and pathways involved in the onset and progression of multiple sclerosis (MS) limits our ability to effectively treat this complex neurological disease. Recent studies explore the role of immune cells at different stages of MS and how they interact with cells of the central nervous system (CNS). The findings presented here begin to question the exclusivity of an antigen-specific cause and highlight how seemingly distinct immune cell types can share common functions that drive disease. Innovative techniques further expose new disease-associated immune cell populations and reinforce how environmental context is critical to their phenotype and subsequent role in disease. Importantly, the differentiation of immune cells into a pathogenic state is potentially reversible through therapeutic manipulation. As such, understanding the mechanisms that provide plasticity to causal cell types is likely key to uncoupling these disease processes and may identify novel therapeutic targets that replace the need for cell ablation.

Monocyte programming by cancer therapy

Monocytes in peripheral blood circulation are the precursor of essential cells that control tumor progression, that include tumor-associated macrophages (TAMs), dendritic cells (DCs) and myeloid-derive suppressor cells (MDSC). Monocytes-derived cells orchestrate immune reactions in tumor microenvironment that control disease outcome and efficiency of cancer therapy. Four major types of anti-cancer therapy, surgery, radiotherapy, chemotherapy, and most recent immunotherapy, affect tumor-associated macrophage (TAM) polarization and functions. TAMs can also decrease the efficiency of therapy in a tumor-specific way. Monocytes is a major source of TAMs, and are recruited to tumor mass from the blood circulation. However, the mechanisms of monocyte programming in circulation by different therapeutic onsets are only emerging. In our review, we present the state-of-the art about the effects of anti-cancer therapy on monocyte progenitors and their dedifferentiation, on the content of monocyte subpopulations and their transcriptional programs in the circulation, on their recruitment into tumor mass and their potential to give origin for TAMs in tumor-specific microenvironment. We have also summarized very limited available knowledge about genetics that can affect monocyte interaction with cancer therapy, and highlighted the perspectives for the therapeutic targeting of circulating monocytes in cancer patients. We summarized the knowledge about the mediators that affect monocytes fate in all four types of therapies, and we highlighted the perspectives for targeting monocytes to develop combined and minimally invasive anti-cancer therapeutic approaches.

Defining resistance and tolerance traits in Covid-19: towards a stratified medicine approach

Successful host defence against infectious disease involves resistance (reduce pathogen load) and tolerance (reduce tissue damage associated with pathogen presence). Integration of clinical, immunologic, genetic and therapeutic discoveries has identified defects in both of these responses in the progression from SARS-CoV-2 infection to life-threatening coronavirus disease 2019 (Covid-19) lung injury. Early after infection with SARS-CoV-2, resistance can be compromised by a failed type 1 interferon (IFN-I) response, due to direct viral antagonism of induction and signalling, deleterious host genetic variants (IFNAR2, IFNA10, TYK2 and PLSCR1), and neutralizing auto-antibodies directed against IFN-I (predominantly IFN-α). Later in the disease, after pathogen sensing has activated a pro-inflammatory response, a failure to appropriately regulate this response compromises tolerance resulting in virus-independent immunopathology involving the lung and reticuloendothelial system. Monocytes are activated in the periphery (involving M-CSF, GM-CSF, IL-6, NLRP1 inflammasomes, TYK2 and afucosylated anti-spike IgG) then recruited to the lung (involving CCR2::MCP-3/MCP-1 and C5a::C5aR1 axes) as pro-inflammatory monocyte-derived macrophages, resulting in inflammatory lung injury. Phenotypic and genotypic heterogeneity is apparent in all these responses, identifying 'treatable traits' (therapeutically relevant components of inter-individual variation) which could be exploited to achieve a stratified medicine approach to Covid-19. Overall, Covid-19 pathogenesis re-affirms the importance of resistance in surviving an infectious disease and highlights that tolerance is also a central pillar of host defence in humans and can be beneficially modified using host-directed therapies.

PD-1 Inhibitor Combined With Radiotherapy and GM-CSF (PRaG) in Patients With Metastatic Solid Tumors: An Open-Label Phase II Study

Patients with metastatic cancer refractory to standard systemic therapies have a poor prognosis and few therapeutic options. Radiotherapy can shape the tumor microenvironment (TME) by inducing immunogenic cell death and promoting tumor recognition by natural killer cells and T lymphocytes. Granulocyte macrophage-colony stimulating factor (GM-CSF) was known to promote dendric cell maturation and function, and might also induce the macrophage polarization with anti-tumor capabilities. A phase II trial (ChiCTR1900026175) was conducted to assess the clinical efficacy and safety of radiotherapy, PD-1 inhibitor and GM-CSF (PRaG regimen). This trial was registered at http://www.chictr.org.cn/index.aspx. A PRaG cycle consisted of 3 fractions of 5 or 8 Gy delivered for one metastatic lesion from day 1, followed by 200 μg subcutaneous injection of GM-CSF once daily for 2 weeks, and intravenous infusion of PD-1 inhibitor once within one week after completion of radiotherapy. The PRaG regimen was repeated every 21 days for at least two cycles. Once the PRaG therapy was completed, the patient continued PD-1 inhibitor monotherapy until confirmed disease progression or unacceptable toxicity. The primary endpoint was objective response rate (ORR). A total of 54 patients were enrolled with a median follow-up time of 16.4 months. The ORR was 16.7%, and the disease control rate was 46.3% in intent-to-treat patients. Median progression-free survival was 4.0 months (95% confidence interval [CI], 3.3 to 4.8), and median overall survival was 10.5 months (95% CI, 8.7 to 12.2). Grade 3 treatment-related adverse events occurred in five patients (10.0%) and grade 4 in one patient (2.0%). Therefore, the PRaG regimen was well tolerated with acceptable toxicity and may represent a promising salvage treatment for patients with chemotherapy-refractory solid tumors. It is likely that PRaG acts via heating upthe TME with radiotherapy and GM-CSF, which was further boosted by PD-1 inhibitors.

GM-CSF: A Double-Edged Sword in Cancer Immunotherapy

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a cytokine that drives the generation of myeloid cell subsets including neutrophils, monocytes, macrophages, and dendritic cells in response to stress, infections, and cancers. By modulating the functions of innate immune cells that serve as a bridge to activate adaptive immune responses, GM-CSF globally impacts host immune surveillance under pathologic conditions. As with other soluble mediators of immunity, too much or too little GM-CSF has been found to promote cancer aggressiveness. While too little GM-CSF prevents the appropriate production of innate immune cells and subsequent activation of adaptive anti-cancer immune responses, too much of GM-CSF can exhaust immune cells and promote cancer growth. The consequences of GM-CSF signaling in cancer progression are a function of the levels of GM-CSF, the cancer type, and the tumor microenvironment. In this review, we first discuss the secretion of GM-CSF, signaling downstream of the GM-CSF receptor, and GM-CSF’s role in modulating myeloid cell homeostasis. We then outline GM-CSF’s anti-tumorigenic and pro-tumorigenic effects both on the malignant cells and on the non-malignant immune and other cells in the tumor microenvironment. We provide examples of current clinical and preclinical strategies that harness GM-CSF’s anti-cancer potential while minimizing its deleterious effects. We describe the challenges in achieving the Goldilocks effect during administration of GM-CSF-based therapies to patients with cancer. Finally, we provide insights into how technologies that map the immune microenvironment spatially and temporally may be leveraged to intelligently harness GM-CSF for treatment of malignancies.

Qing-Luo-Yin Alleviated Experimental Arthritis in Rats by Disrupting Immune Feedback Between Inflammatory T Cells and Monocytes: Key Evidences from Its Effects on Immune Cell Phenotypes

BACKGROUND

Qing-Luo-Yin (QLY) is an anti-rheumatic herbal formula. Despite the well-investigated therapeutic efficacy of QLY, its immune regulatory properties are largely unknown. CD4+ T cells and monocytes are two key parameters in rheumatoid arthritis (RA). This study investigated the changes in these cells in QLY-treated RA animal models.

MATERIALS AND METHODS

RA models were induced in male SD rats and were orally treated with QLY. Dynamic metabolic changes in collagen-induced arthritis (CIA) rats were monitored by 1H NMR approach. The immunity profiles of CIA and adjuvant-induced arthritis (AIA) rats were evaluated using immunohistochemical, PCR, ELISA, cytokine chip, flow cytometry, and immunofluorescence experiments. The bioactive components in QLY were identified by bioinformatic-guided LC-MS analyses. The compounds with high abundance in QLY decoction and easily absorbed were taken as key anti-rheumatic components and used to treat blood-derived immune cells using in vitro experiments.

RESULTS

The results indicated that QLY decreased Th17 cells frequency and T cells-released IL-6, IL-17 and GM-CSF in CIA rats, which was attributed to the impaired lymphocyte maturation and altered differentiation. QLY inhibited lactic acid production and inflammatory polarization in the monocytes during the peak period of AIA and CIA. AIA monocytes elicited significant increase in Th17 cells counts, IL-6 and IL-1β secretion in co-cultured splenocytes, which was abrogated by QLY. QLY-containing serum suppressed the phosphorylation of JNK and p65 in AIA lymphocyte-stimulated normal monocytes and consequently inhibited iNOS and IL-1β expression as well as IL-6 and IL-1β production. Matrine, sinomenine and sophocarpine were identified as major bioactive compounds in QLY. These identified compounds effectively inhibited the development of inflammatory T cells using concentrations detected in QLY-treated rats. At higher concentrations (20-fold increase), the chemical stimuli significantly suppressed the production of IL-1β in AIA monocytes by inhibiting JNK and p65 pathways.

CONCLUSION

By targeting inflammatory T cells and monocytes as well as disrupting their interplay, QLY improved immune environment in RA models especially during the active stages of disease.

Obesity Prolongs the Inflammatory Response in Mice After Severe Trauma and Attenuates the Splenic Response to the Inflammatory Reflex

Thoracic traumas with extra-thoracic injuries result in an immediate, complex host response. The immune response requires tight regulation and can be influenced by additional risk factors such as obesity, which is considered a state of chronic inflammation. Utilizing high-dimensional mass and regular flow cytometry, we define key signatures of obesity-related alterations of the immune system during the response to the trauma. In this context, we report a modification in important components of the splenic response to the inflammatory reflex in obese mice. Furthermore, during the response to trauma, obese mice exhibit a prolonged increase of neutrophils and an early accumulation of inflammation associated CCR2⁺CD62L⁺Ly6C^hi monocytes in the blood, contributing to a persistent inflammatory phase. Moreover, these mice exhibit differences in migration patterns of monocytes to the traumatized lung, resulting in decreased numbers of regenerative macrophages and an impaired M1/M2 switch in traumatized lungs. The findings presented in this study reveal an attenuation of the inflammatory reflex in obese mice, as well as a disturbance of the monocytic compartment contributing to a prolonged inflammation phase resulting in fewer phenotypically regenerative macrophages in the lung of obese mice.

The Role of Distinct Subsets of Macrophages in the Pathogenesis of MS and the Impact of Different Therapeutic Agents on These Populations

Multiple sclerosis (MS) is a demyelinating inflammatory disorder of the central nervous system (CNS). Besides the vital role of T cells, other immune cells, including B cells, innate immune cells, and macrophages (MФs), also play a critical role in MS pathogenesis. Tissue-resident MФs in the brain’s parenchyma, known as microglia and monocyte-derived MФs, enter into the CNS following alterations in CNS homeostasis that induce inflammatory responses in MS. Although the neuroprotective and anti-inflammatory actions of monocyte-derived MФs and resident MФs are required to maintain CNS tolerance, they can release inflammatory cytokines and reactivate primed T cells during neuroinflammation. In the CNS of MS patients, elevated myeloid cells and activated MФs have been found and associated with demyelination and axonal loss. Thus, according to the role of MФs in neuroinflammation, they have attracted attention as a therapeutic target. Also, due to their different origin, location, and turnover, other strategies may require to target the various myeloid cell populations. Here we review the role of distinct subsets of MФs in the pathogenesis of MS and different therapeutic agents that target these cells.

CAR-T Cell Therapy: Mechanism, Management, and Mitigation of Inflammatory Toxicities

Engineered T cell therapies such as chimeric antigen receptor (CAR) expressing T cells (CAR-T cells) have great potential to treat many human diseases; however, inflammatory toxicities associated with these therapies present safety risks and can greatly limit its widespread use. This article briefly reviews our current understanding of mechanisms for inflammatory toxicities during CAR T-cell therapy, current strategies for management and mitigation of these risks and highlights key areas of knowledge gap for future research.

Optimizing the Treatment Schedule of Radiotherapy Combined With Anti-PD-1/PD-L1 Immunotherapy in Metastatic Cancers

Immune checkpoint inhibitors (ICIs) targeting programmed cell death protein-1 (PD-1), and programmed cell death ligand-1 (PD-L1) have been approved for a variety of malignant tumors and are widely used to treat patients with metastatic disease. However, the efficacy of PD-1 inhibitors is limited due to tumor heterogeneity, high tumor burden, and "cold" tumor microenvironment. Radiotherapy can improve the anti-tumor effects of PD-1/PD-L1 inhibitors in various ways. As a new radiotherapy method, stereotactic body radiotherapy (SBRT) or hypofractionated radiotherapy (HFRT) provides higher doses per fraction to the target lesions, thus achieving immune activation effects and overcoming tumor resistance to anti-PD-1/PD-L1 treatment, which significantly improves the local and distant control of tumors. However, for different metastatic situations, radiotherapy plays different roles in the combination therapy. In oligometastatic status, radiotherapy can be used as a local radical treatment aiming to eliminate cancers in cooperation with systemic PD-1 inhibitors. In other circumstances, like bulky metastasis or multiple metastatic tumors, radiotherapy can be used as adjuvant to systemic immunotherapy. This review focuses on the underlying mechanisms and optimization strategies for the combination of radiotherapy and anti-PD-1/PD-L1 therapy in metastatic disease.

Colony Stimulating Factors in Early Feline Infectious Peritonitis Virus Infection of Monocytes and in End Stage Feline Infectious Peritonitis; A Combined In Vivo And In Vitro Approach

Feline coronavirus (FCoV) infection initiates monocyte-associated viremia and viral persistence. Virus-infected, -activated monocytes also trigger feline infectious peritonitis (FIP), a fatal systemic disease of felids typified by granulomatous (peri)phlebitis. Currently, the exact mechanisms inducing monocyte activation and FIP are unknown. This study attempted to identify the potential immediate effect of virulent FCoV on colony-stimulating factor (CSF) (granulocyte (G)-CSF, monocyte (M)-CSF and granulocyte-monocyte (GM)-CSF levels through in vitro assessment, alongside prototypical pro- and anti-inflammatory mediators (interleukin (IL)-1, IL-6, IL-12p40, tumor necrosis factor (TNF)-α, and IL-10); this was assessed alongside the in vivo situation in the hemolymphatic tissues of cats euthanized with natural end-stage FIP. For the in vitro work, isolated monocytes from SPF cats were cultured short-term and infected with the FIP virus (FIPV) strain DF2. Mediator transcription was assessed by quantitative reverse transcriptase PCR (RT-qPCR) at 3, 6 and 9 h post infection (hpi), and in the post-mortem samples of bone marrow, spleen, and mesenteric lymph nodes (MLN) of cats with FIP. We observed limited and transient changes in cytokine transcription in monocytes after infection, i.e., a significant increase of IL-6 at 3 hpi and of GM-CSF over the 3 and 6 hpi period, whereas M-CSF was significantly decreased at 9 hpi, with a limited effect of age. The findings indicate that the infection induces expansion of the monocyte/macrophage population, which would ensure the sufficient supply of cells for consistent viral replication. In natural disease, the only upregulation was of G-CSF in the MLN, suggesting either immune exhaustion or an active downregulation by the host as part of its viral response.