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International Journal of Molecular... Nov 2019In the era of novel agents and immunotherapies in solid and liquid tumors, there is an emerging need to understand the cross-talk between the neoplastic cells, the host... (Review)
Review
In the era of novel agents and immunotherapies in solid and liquid tumors, there is an emerging need to understand the cross-talk between the neoplastic cells, the host immune system, and the microenvironment to mitigate proliferation, survival, migration and resistance to drugs. In the microenvironment of hematological tumors there are cells belonging to the normal bone marrow, extracellular matrix proteins, adhesion molecules, cytokines, and growth factors produced by both stromal cells and neoplastic cells themselves. In this context, myeloid suppressor cells are an emerging sub-population of regulatory myeloid cells at different stages of differentiation involved in cancer progression and chronic inflammation. In this review, monocytic myeloid derived suppressor cells and their potential clinical implications are discussed to give a comprehensive vision of their contribution to lymphoproliferative and myeloid disorders.
Topics: Animals; Bone Marrow Cells; Cell Communication; Cell Differentiation; Disease Progression; Hematologic Neoplasms; Humans; Monocytes; Myeloid-Derived Suppressor Cells; Stromal Cells; Tumor Microenvironment
PubMed: 31683978
DOI: 10.3390/ijms20215459 -
Immunology Apr 2023Immunoparalysis is associated with poorer outcomes in the paediatric intensive care unit (PICU) setting. We aimed to determine the group of patients with higher chances...
Immunoparalysis is associated with poorer outcomes in the paediatric intensive care unit (PICU) setting. We aimed to determine the group of patients with higher chances of immunoparalysis and correlate this status with increased risks of nosocomial infection and adverse clinical parameters. We conducted an exploratory study with prospective data collection in a university-affiliated tertiary medical, surgical, and cardiac PICU. Fifteen patients with multiple organ dysfunction syndrome were included over a period of 6 months. Monocyte's human leucocyte antigen (HLA)-DR expression and tumour necrosis factor (TNF)-α and interleukin (IL)-6 production were measured by flow-cytometry at three time points (T1 = 1-2 days; T2 = 3-5 days; T3 = 6-8 days). Using the paediatric logistic organ dysfunction-2 score to assess initial disease severity, we established the optimal cut-off values of the evaluated parameters to identify the subset of patients with a higher probability of immunoparalysis. A comparative analysis was performed between them. Sixty per cent were males; the median age was 4.1 years. Considering the presence of two criteria in T1 (classical monocytes mean fluorescence intensity [MFI] for HLA-DR ≤ 1758.5, area under the curve (AUC) = 0.775; and frequency of monocytes producing IL-6 ≤ 68.5%, AUC = 0.905) or in T3 (classical monocytes MFI of HLA-DR ≤ 2587.5, AUC = 0.675; and frequency of monocytes producing TNF-α ≤ 93.5%, AUC = 0.833), a variable to define immunoparalysis was obtained (100% sensitivity, 81.5% specificity). Forty per cent of patients were assigned to the immunoparalysis group. In this: a higher frequency of nosocomial infection (p = 0.011), vasoactive inotropic score (p = 0.014) and length of hospital stay (p = 0.036) was observed. In the subgroup with the diagnosis of sepsis/septic shock (n = 5), patients showed higher percentages of non-classical monocytes (p = 0.004). No mortality was recorded. A reduction in classical monocytes HLA-DR expression with lower frequencies of monocytes producing TNF-α and IL-6 during the first week of critical illness, appears to be a good marker of immunoparalysis; these findings relate to an increased risk of nosocomial infection and deleterious outcomes. The increased frequency of non-classical monocytes in patients with sepsis/septic shock is suggestive of a better prognosis.
Topics: Male; Humans; Child; Child, Preschool; Female; Shock, Septic; Tumor Necrosis Factor-alpha; Interleukin-6; Critical Illness; HLA-DR Antigens; Cross Infection; Monocytes; Sepsis
PubMed: 36279244
DOI: 10.1111/imm.13595 -
Cancer Metastasis Reviews Jun 2021Cancer progression largely depends on tumor blood vessels as well on immune cell infiltration. In various tumors, vascular cells, namely endothelial cells (ECs) and... (Review)
Review
Cancer progression largely depends on tumor blood vessels as well on immune cell infiltration. In various tumors, vascular cells, namely endothelial cells (ECs) and pericytes, strongly regulate leukocyte infiltration into tumors and immune cell activation, hence the immune response to cancers. Recently, a lot of compelling studies unraveled the molecular mechanisms by which tumor vascular cells regulate monocyte and tumor-associated macrophage (TAM) recruitment and phenotype, and consequently tumor progression. Reciprocally, TAMs and monocytes strongly modulate tumor blood vessel and tumor lymphatic vessel formation by exerting pro-angiogenic and lymphangiogenic effects, respectively. Finally, the interaction between monocytes/TAMs and vascular cells is also impacting several steps of the spread of cancer cells throughout the body, a process called metastasis. In this review, the impact of the bi-directional dialog between blood vascular cells and monocytes/TAMs in the regulation of tumor progression is discussed. All together, these data led to the design of combinations of anti-angiogenic and immunotherapy targeting TAMs/monocyte whose effects are briefly discussed in the last part of this review.
Topics: Animals; Cell Communication; Disease Progression; Humans; Macrophages; Monocytes; Neoplasms; Neoplastic Stem Cells; Neovascularization, Pathologic; Tumor Microenvironment
PubMed: 33783686
DOI: 10.1007/s10555-021-09958-2 -
Journal of Leukocyte Biology Mar 2021Macrophages are key immune cells in the activation and regulation of immune responses. These cells are present in all tissues under homeostatic conditions and in many... (Review)
Review
Macrophages are key immune cells in the activation and regulation of immune responses. These cells are present in all tissues under homeostatic conditions and in many disease settings. Macrophages can exhibit a wide range of phenotypes depending on local and systemic cues that drive the differentiation and activation process. Macrophage heterogeneity is also defined by their ontogeny. Tissue macrophages can either derive from circulating blood monocytes or are seeded as tissue-resident macrophages during embryonic development. In humans, the study of in vivo-generated macrophages is often difficult with laborious and cell-changing isolation procedures. Therefore, translatable, reproducible, and robust in vitro models for human macrophages in health and disease are necessary. Most of the methods for studying monocyte-derived macrophages are based on the use of limited factors to differentiate the monocytes into macrophages. Current knowledge shows that the in vivo situation is more complex, and a wide range of molecules in the tissue microenvironment promote and impact on monocyte to macrophage differentiation as well as activation. In this review, macrophage heterogeneity is discussed and the human in vitro models that can be applied for research, especially for monocyte-derived macrophages. We also focus on new molecules (IL-34, platelet factor 4, etc.) used to generate macrophages expressing different phenotypes.
Topics: Cell Differentiation; Humans; Macrophages; Models, Biological; Monocytes; Phenotype
PubMed: 32592421
DOI: 10.1002/JLB.1RU0620-018R -
Thrombosis Research Aug 2023Tissue factor expression on monocytes is implicated in the pathophysiology of sepsis-induced coagulopathy. How tissue factor is expressed by monocyte subsets (classical,...
INTRODUCTION
Tissue factor expression on monocytes is implicated in the pathophysiology of sepsis-induced coagulopathy. How tissue factor is expressed by monocyte subsets (classical, intermediate and non-classical) is unknown.
METHODS
Monocytic tissue factor surface expression was investigated during three conditions. Primary human monocytes and microvascular endothelial cell co-cultures were used for in vitro studies. Volunteers received a bolus of lipopolysaccharide (2 ng/kg) to induce endotoxemia. Patients with sepsis, or controls with critical illness unrelated to sepsis, were recruited from four intensive care units.
RESULTS
Contact with endothelium and stimulation with lipopolysaccharide reduced the proportion of intermediate monocytes. Lipopolysaccharide increased tissue factor surface expression on classical and non-classical monocytes. Endotoxemia induced profound, transient monocytopenia, along with activation of coagulation pathways. In the remaining circulating monocytes, tissue factor was up-regulated in intermediate monocytes, though approximately 60 % of individuals (responders) up-regulated tissue factor across all monocyte subsets. In critically ill patients, tissue factor expression on intermediate and non-classical monocytes was significantly higher in patients with established sepsis than among non-septic patients. Upon recovery of sepsis, expression of tissue factor increased significantly in classical monocytes.
CONCLUSION
Tissue factor expression in monocyte subsets varies significantly during health, endotoxemia and sepsis.
Topics: Humans; Monocytes; Endotoxemia; Thromboplastin; Thromboinflammation; Lipopolysaccharides; Sepsis
PubMed: 37263122
DOI: 10.1016/j.thromres.2023.05.018 -
Frontiers in Immunology 2021Diet has been associated with several metabolic diseases and may impact immunity. Increased consumption of meals with high oxalate content may stimulate urinary calcium...
UNLABELLED
Diet has been associated with several metabolic diseases and may impact immunity. Increased consumption of meals with high oxalate content may stimulate urinary calcium oxalate (CaOx) crystals, which are precursors to CaOx kidney stones. We previously reported that CaOx stone formers have decreased monocyte cellular bioenergetics compared to healthy participants and oxalate reduces monocyte metabolism and redox status . The purpose of this study was to investigate whether dietary oxalate loading impacts monocyte cellular bioenergetics, mitochondrial complex activity, and inflammatory signaling in humans. Healthy participants (n = 40; 31.1 ± 1.3 years) with a BMI of 24.9 ± 0.6 kg/m consumed a controlled low oxalate diet for 3 days before drinking a blended preparation of fruits and vegetables containing a large amount of oxalate. Blood and urine were collected before (pre-oxalate) and for 5 h after the oxalate load to assess urinary oxalate levels, monocyte cellular bioenergetics and mitochondrial complex activity, and plasma cytokine/chemokine levels. Urinary oxalate levels significantly increased in post-oxalate samples compared to pre-oxalate samples. Monocyte cellular bioenergetics, mitochondrial complex I activity, and plasma cytokine and chemokine levels were altered to varying degrees within the study cohort. We demonstrate for the first time that dietary oxalate loading may impact monocyte metabolism and immune response in a cohort of healthy adults, but these response are variable. Further studies are warranted to understand oxalate mediated mechanisms on circulating monocytes and how this potentially influences CaOx kidney stone formation.
CLINICAL TRIAL REGISTRATION
ClinicalTrials.gov, identifier NCT03877276.
Topics: Adult; Biomarkers; Dietary Supplements; Electron Transport Chain Complex Proteins; Energy Metabolism; Female; Humans; Inflammation; Leukocyte Count; Male; Mitochondria; Monocytes; Oxalates; Signal Transduction; Urinalysis
PubMed: 33732242
DOI: 10.3389/fimmu.2021.617508 -
Hepatology International Jun 2023Acute-on-chronic liver failure (ACLF) has a high prevalence and short-term mortality. Monocytes play an important role in the development of ACLF. However, the monocyte...
OBJECTIVE
Acute-on-chronic liver failure (ACLF) has a high prevalence and short-term mortality. Monocytes play an important role in the development of ACLF. However, the monocyte subpopulations with unique features and functions in ACLF and associated with disease progression remain poorly understood. We investigated the specific monocyte subpopulations associated with ACLF progression and their roles in inflammatory responses using the single-cell RNA sequencing (scRNA-seq).
METHODS
We performed scRNA-seq on 17,310 circulating monocytes from healthy controls and ACLF patients and genetically defined their subpopulations to characterize specific monocyte subpopulations associated with ACLF progression.
RESULTS
Five monocyte subpopulations were obtained, including pro-inflammatory monocytes, CD16 monocytes, HLA monocytes, megakaryocyte-like monocytes, and NK-like monocytes. Comparisons of the monocytes between ACLF patients and healthy controls showed that the pro-inflammatory monocytes had the most significant gene changes, among which the expressions of genes related to inflammatory responses and cell metabolism were significantly increased while the genes related to cell cycle progression were significantly decreased. Furthermore, compared with the ACLF survival group, the ACLF death group had significantly higher expressions of pro-inflammatory cytokines (e.g., IL-6) and their receptors, chemokines (e.g., CCL4 and CCL5), and inflammation-inducing factors (e.g., HES4). Additionally, validation using scRNA-seq and flow cytometry revealed the presence of a cell type-specific transcriptional signature of pro-inflammatory monocytes THBS1, whose production might reflect the disease progression and poor prognosis.
CONCLUSIONS
We present the accurate classification, molecular markers, and signaling pathways of monocytes associated with ACLF progression. Therapies targeting pro-inflammatory monocytes may be a promising approach for blocking ACLF progression.
Topics: Humans; Monocytes; Acute-On-Chronic Liver Failure; Cytokines; Inflammation; Disease Progression
PubMed: 36626090
DOI: 10.1007/s12072-022-10472-y -
Frontiers in Immunology 2023Monocyte exhaustion characterized by immune-suppressive features can develop during sepsis and contribute to adverse patient outcomes. However, molecular mechanisms...
Monocyte exhaustion characterized by immune-suppressive features can develop during sepsis and contribute to adverse patient outcomes. However, molecular mechanisms responsible for the establishment of immune-suppressive monocytes with reduced expression of immune-enhancing mediators such as CD86 during sepsis are not well understood. In this study, we identified that the TLR4 intracellular adaptor TRAM plays a key role in mediating the sustained reduction of CD86 expression on exhausted monocytes and generating an immune-suppressive monocyte state. TRAM contributes to the prolonged suppression of CD86 through inducing TAX1BP1 as well as SARM1, collectively inhibiting Akt and NFκB. TRAM deficient mice are protected from cecal slurry-induced experimental sepsis and retain immune-competent monocytes with CD86 expression. Our data reveal a key molecular circuitry responsible for monocyte exhaustion and provide a viable target for rejuvenating functional monocytes and treating sepsis.
Topics: Animals; Humans; Mice; Armadillo Domain Proteins; B7-2 Antigen; Cytoskeletal Proteins; Disease Models, Animal; Immune System Exhaustion; Intracellular Signaling Peptides and Proteins; Membrane Proteins; Mice, Inbred C57BL; Monocytes; NF-kappa B p50 Subunit; Proto-Oncogene Proteins c-akt; Sepsis; Signal Transduction; Mice, Knockout; Receptors, Interleukin
PubMed: 38162637
DOI: 10.3389/fimmu.2023.1297329 -
Circulation Research Mar 2021Circulating monocytes can have proinflammatory or proreparative phenotypes. The endogenous signaling molecules and pathways that regulate monocyte polarization in vivo...
RATIONALE
Circulating monocytes can have proinflammatory or proreparative phenotypes. The endogenous signaling molecules and pathways that regulate monocyte polarization in vivo are poorly understood. We have shown that platelet-derived β2M (β-2 microglobulin) and TGF-β (transforming growth factor β) have opposing effects on monocytes by inducing inflammatory and reparative phenotypes, respectively, but each bind and signal through the same receptor. We now define the signaling pathways involved.
OBJECTIVE
To determine the molecular mechanisms and signal transduction pathways by which β2M and TGF-β regulate monocyte responses both in vitro and in vivo.
METHODS AND RESULTS
Wild-type- (WT) and platelet-specific β2M knockout mice were treated intravenously with either β2M or TGF-β to increase plasma concentrations to those in cardiovascular diseases. Elevated plasma β2M increased proinflammatory monocytes, while increased plasma TGFβ increased proreparative monocytes. TGF-βR (TGF-β receptor) inhibition blunted monocyte responses to both β2M and TGF-β in vivo. Using imaging flow cytometry, we found that β2M decreased monocyte SMAD2/3 nuclear localization, while TGF-β promoted SMAD nuclear translocation but decreased noncanonical/inflammatory (JNK [jun kinase] and NF-κB [nuclear factor-κB] nuclear localization). This was confirmed in vitro using both imaging flow cytometry and immunoblots. β2M, but not TGF-β, promoted ubiquitination of SMAD3 and SMAD4, that inhibited their nuclear trafficking. Inhibition of ubiquitin ligase activity blocked noncanonical SMAD-independent monocyte signaling and skewed monocytes towards a proreparative monocyte response.
CONCLUSIONS
Our findings indicate that elevated plasma β2M and TGF-β dichotomously polarize monocytes. Furthermore, these immune molecules share a common receptor but induce SMAD-dependent canonical signaling (TGF-β) versus noncanonical SMAD-independent signaling (β2M) in a ubiquitin ligase dependent manner. This work has broad implications as β2M is increased in several inflammatory conditions, while TGF-β is increased in fibrotic diseases. Graphic Abstract: A graphic abstract is available for this article.
Topics: Animals; Cell Differentiation; Cells, Cultured; Humans; MAP Kinase Kinase 4; Mice; Mice, Inbred C57BL; Monocytes; NF-kappa B; Receptors, Transforming Growth Factor beta; Signal Transduction; Smad Proteins; THP-1 Cells; beta 2-Microglobulin
PubMed: 33508948
DOI: 10.1161/CIRCRESAHA.120.317119 -
Scientific Reports Jul 2020Following major trauma, sepsis or surgery, some patients exhibit an impaired monocyte inflammatory response that is characterized by a decreased response to a subsequent...
Following major trauma, sepsis or surgery, some patients exhibit an impaired monocyte inflammatory response that is characterized by a decreased response to a subsequent bacterial challenge. To investigate this poorly understood phenomenon, we adopted an in-vitro model of endotoxin tolerance utilising primary human CD14 + monocytes to focus on the effect of impairment on IκKα/β, a critical part of the NFκB pathway. Impaired monocytes had decreased IκKα mRNA and protein expression and decreased phosphorylation of the IκKα/β complex. The impaired monocyte secretome demonstrated a distinct cytokine/chemokine footprint from the naïve monocyte, and that TNF-α was the most sensitive cytokine or chemokine in this setting of impairment. Inhibition of IκKα/β with a novel selective inhibitor reproduced the impaired monocyte phenotype with decreased production of TNF-α, IL-6, IL-12p70, IL-10, GM-CSF, VEGF, MIP-1β, TNF-β, IFN-α2 and IL-7 in response to an LPS challenge. Surgical patients with infection also exhibited an impaired monocyte phenotype and had decreased SITPEC, TAK1 and MEKK gene expression, which are important for IκKα/β activation. Our results emphasize that impaired monocyte function is, at least in part, related to dysregulated IκKα/β activation, and that IκKα/β is likely involved in mounting a sufficient monocyte inflammatory response. Future studies may wish to focus on adjuvant therapies that augment IκKα/β function to restore monocyte function in this clinically important problem.
Topics: Adult; Chemokines; Cytokines; Female; Humans; I-kappa B Kinase; Inflammation; Lipopolysaccharides; Male; Middle Aged; Monocytes; RNA, Messenger
PubMed: 32699255
DOI: 10.1038/s41598-020-68018-x