scholarly journals The Enigma of Low-Density Granulocytes in Humans: Complexities in the Characterization and Function of LDGs during Disease

Pathogens ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1091
Author(s):  
Brittany G. Seman ◽  
Cory M. Robinson
Keyword(s):  
Immune Cells ◽  
Suppressor Cells ◽  
Cell Types ◽  
Low Density ◽  
Myeloid Derived Suppressor Cells ◽  
Disease States ◽  
Isolation Techniques ◽  
Microbial Infections ◽  
And Function

Low-density granulocytes (LDGs) have been characterized as important immune cells during healthy and disease states in humans, including microbial infections, cancer, and autoimmune dysfunction. However, the classification of this cell type is similar to other immune cells (e.g., neutrophils, myeloid-derived suppressor cells) and ambiguous functional standards have rendered LDG identification and isolation daunting. Furthermore, most research involving LDGs has mainly focused on adult cells and subjects, leaving increased uncertainty surrounding younger populations, especially in vulnerable neonatal groups where LDG numbers are elevated. This review aims to bring together the current research in the field of LDG biology in the context of immunity to disease, with a focus on infection. In addition, we propose to highlight the gaps in the field that, if filled, could improve upon isolation techniques and functional characterizations for LDGs separate from neutrophils and myeloid-derived suppressor cells (MDSCs). This will not only enhance understanding of LDGs during disease processes and how they differ from other cell types but will also aid in the interpretation of comparative studies and results with the potential to inform development of novel therapeutics to improve disease states in patients.

scholarly journals New Insights into the Multifaceted Role of Myeloid-Derived Suppressor Cells (MDSCs) in High-Grade Gliomas: From Metabolic Reprograming, Immunosuppression, and Therapeutic Resistance to Current Strategies for Targeting MDSCs

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 893
Author(s):  
Senthilnath Lakshmanachetty ◽  
Joselyn Cruz-Cruz ◽  
Eric Hoffmeyer ◽  
Allison P. Cole ◽  
Siddhartha S. Mitra
Keyword(s):  
Bone Marrow ◽  
Immune Cells ◽  
Suppressor Cells ◽  
Standard Of Care ◽  
High Grade Glioma ◽  
Cell Types ◽  
Current Treatment ◽  
High Grade ◽  
Myeloid Derived Suppressor Cells ◽  
High Grade Gliomas

Cancer cells “hijack” host immune cells to promote growth, survival, and metastasis. The immune microenvironment of high-grade gliomas (HGG) is a complex and heterogeneous system, consisting of diverse cell types such as microglia, bone marrow-derived macrophages (BMDMs), myeloid-derived suppressor cells (MDSCs), dendritic cells, natural killer (NK) cells, and T-cells. Of these, MDSCs are one of the major tumor-infiltrating immune cells and are correlated not only with overall worse prognosis but also poor clinical outcomes. Upon entry from the bone marrow into the peripheral blood, spleen, as well as in tumor microenvironment (TME) in HGG patients, MDSCs deploy an array of mechanisms to perform their immune and non-immune suppressive functions. Here, we highlight the origin, function, and characterization of MDSCs and how they are recruited and metabolically reprogrammed in HGG. Furthermore, we discuss the mechanisms by which MDSCs contribute to immunosuppression and resistance to current therapies. Finally, we conclude by summarizing the emerging approaches for targeting MDSCs alone as a monotherapy or in combination with other standard-of-care therapies to improve the current treatment of high-grade glioma patients.

Sympathetic nervous tone limits the development of myeloid-derived suppressor cells

2020 ◽  
Vol 5 (51) ◽  
pp. eaay9368 ◽  
Author(s):  
James T. Nevin ◽  
Marmar Moussa ◽  
William L. Corwin ◽  
Ion I. Mandoiu ◽  
Pramod K. Srivastava
Keyword(s):  
Tumor Immunity ◽  
Immune Cells ◽  
Suppressor Cells ◽  
Sympathetic Nerves ◽  
Myeloid Derived Suppressor Cells ◽  
Tumor Bearing ◽  
Adaptive Immune Cells ◽  
Promote Tumor Growth ◽  
Sympathetic Nervous ◽  
And Function

Sympathetic nerves that innervate lymphoid organs regulate immune development and function by releasing norepinephrine that is sensed by immune cells via their expression of adrenergic receptors. Here, we demonstrate that ablation of sympathetic nervous system (SNS) signaling suppresses tumor immunity, and we dissect the mechanism of such immune suppression. We report that disruption of the SNS in mice removes a critical α-adrenergic signal required for maturation of myeloid cells in normal and tumor-bearing mice. In tumor-bearing mice, disruption of the α-adrenergic signal leads to the accumulation of immature myeloid-derived suppressor cells (MDSCs) that suppress tumor immunity and promote tumor growth. Furthermore, we show that these SNS-responsive MDSCs drive expansion of regulatory T cells via secretion of the alarmin heterodimer S100A8/A9, thereby compounding their immunosuppressive activity. Our results describe a regulatory framework in which sympathetic tone controls the development of innate and adaptive immune cells and influences their activity in health and disease.

scholarly journals Fatty Acid Metabolism in Myeloid-Derived Suppressor Cells and Tumor-Associated Macrophages: Key Factor in Cancer Immune Evasion

Cancers ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 250
Author(s):  
Sophiya Siddiqui ◽  
Rainer Glauben
Keyword(s):  
Fatty Acids ◽  
Cancer Progression ◽  
Immune Cells ◽  
Suppressor Cells ◽  
Cell Types ◽  
Eukaryotic Cell ◽  
Metabolic Reprogramming ◽  
Myeloid Derived Suppressor Cells ◽  
Tumor Associated Macrophages ◽  
Key Factor

The tumor microenvironment (TME) comprises various cell types, soluble factors, viz, metabolites or cytokines, which together play in promoting tumor metastasis. Tumor infiltrating immune cells play an important role against cancer, and metabolic switching in immune cells has been shown to affect activation, differentiation, and polarization from tumor suppressive into immune suppressive phenotypes. Macrophages represent one of the major immune infiltrates into TME. Blood monocyte-derived macrophages and myeloid derived suppressor cells (MDSCs) infiltrating into the TME potentiate hostile tumor progression by polarizing into immunosuppressive tumor-associated macrophages (TAMs). Recent studies in the field of immunometabolism focus on metabolic reprogramming at the TME in polarizing tumor-associated macrophages (TAMs). Lipid droplets (LD), detected in almost every eukaryotic cell type, represent the major source for intra-cellular fatty acids. Previously, LDs were mainly described as storage sites for fatty acids. However, LDs are now recognized to play an integral role in cellular signaling and consequently in inflammation and metabolism-mediated phenotypical changes in immune cells. In recent years, the role of LD dependent metabolism in macrophage functionality and phenotype has been being investigated. In this review article, we discuss fatty acids stored in LDs, their role in modulating metabolism of tumor-infiltrating immune cells and, therefore, in shaping the cancer progression.

scholarly journals The Role of Myeloid-Derived Suppressor Cells (MDSCs) in the Development and/or Progression of Endometriosis-State of the Art

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 677
Author(s):  
Dorota Suszczyk ◽  
Wiktoria Skiba ◽  
Joanna Jakubowicz-Gil ◽  
Jan Kotarski ◽  
Iwona Wertel
Keyword(s):  
Ovarian Cancer ◽  
T Cells ◽  
Chronic Inflammation ◽  
Immune Cells ◽  
Suppressor Cells ◽  
Myeloid Derived Suppressor Cells ◽  
Immunological Diseases ◽  
Underlying Mechanisms ◽  
And Function ◽  
The Impact

Endometriosis (EMS) is a common gynecological disease characterized by the presence of endometrial tissue outside the uterus. Approximately 10% of women around the world suffer from this disease. Recent studies suggest that endometriosis has potential to transform into endometriosis-associated ovarian cancer (EAOC). Endometriosis is connected with chronic inflammation and changes in the phenotype, activity, and function of immune cells. The underlying mechanisms include quantitative and functional disturbances of neutrophils, monocytes/macrophages (MO/MA), natural killer cells (NK), and T cells. A few reports have shown that immunosuppressive cells such as regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs) may promote the progression of endometriosis. MDSCs are a heterogeneous population of immature myeloid cells (dendritic cells, granulocytes, and MO/MA precursors), which play an important role in the development of immunological diseases such as chronic inflammation and cancer. The presence of MDSCs in pathological conditions correlates with immunosuppression, angiogenesis, or release of growth factors and cytokines, which promote progression of these diseases. In this paper, we review the impact of MDSCs on different populations of immune cells, focusing on their immunosuppressive role in the immune system, which may be related with the pathogenesis and/or progression of endometriosis and its transformation into ovarian cancer.

scholarly journals Myeloid-Derived Suppressor Cells and Pancreatic Cancer: Implications in Novel Therapeutic Approaches

Cancers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1627 ◽  
Author(s):  
Anita Thyagarajan ◽  
Mamdouh Salman A. Alshehri ◽  
Kelly L.R. Miller ◽  
Catherine M. Sherwin ◽  
Jeffrey B. Travers ◽  
...  
Keyword(s):  
Survival Rates ◽  
Suppressor Cells ◽  
Cell Types ◽  
Therapeutic Agents ◽  
Ductal Adenocarcinoma ◽  
Cancer Therapies ◽  
Myeloid Derived Suppressor Cells ◽  
Tumor Resistance ◽  
Cellular Mechanisms ◽  
Immunosuppressive Cell

Pancreatic ductal adenocarcinoma (PDAC) remains a devastating human malignancy with poor prognosis and low survival rates. Several cellular mechanisms have been linked with pancreatic carcinogenesis and also implicated in inducing tumor resistance to known therapeutic regimens. Of various factors, immune evasion mechanisms play critical roles in tumor progression and impeding the efficacy of cancer therapies including PDAC. Among immunosuppressive cell types, myeloid-derived suppressor cells (MDSCs) have been extensively studied and demonstrated to not only support PDAC development but also hamper the anti-tumor immune responses elicited by therapeutic agents. Notably, recent efforts have been directed in devising novel approaches to target MDSCs to limit their effects. Multiple strategies including immune-based approaches have been explored either alone or in combination with therapeutic agents to target MDSCs in preclinical and clinical settings of PDAC. The current review highlights the roles and mechanisms of MDSCs as well as the implications of this immunomodulatory cell type as a potential target to improve the efficacy of therapeutic regimens for PDAC.

scholarly journals Single cell analysis reveals immune cell–adipocyte crosstalk regulating the transcription of thermogenic adipocytes

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Prashant Rajbhandari ◽  
Douglas Arneson ◽  
Sydney K Hart ◽  
In Sook Ahn ◽  
Graciel Diamante ◽  
...  
Keyword(s):  
Single Cell ◽  
Immune Cells ◽  
Immune Cell ◽  
Single Cell Analysis ◽  
Metabolic Response ◽  
Cell Types ◽  
Specific Cell ◽  
Beneficial Effects ◽  
Thermogenic Adipocytes ◽  
And Function

Immune cells are vital constituents of the adipose microenvironment that influence both local and systemic lipid metabolism. Mice lacking IL10 have enhanced thermogenesis, but the roles of specific cell types in the metabolic response to IL10 remain to be defined. We demonstrate here that selective loss of IL10 receptor α in adipocytes recapitulates the beneficial effects of global IL10 deletion, and that local crosstalk between IL10-producing immune cells and adipocytes is a determinant of thermogenesis and systemic energy balance. Single Nuclei Adipocyte RNA-sequencing (SNAP-seq) of subcutaneous adipose tissue defined a metabolically-active mature adipocyte subtype characterized by robust expression of genes involved in thermogenesis whose transcriptome was selectively responsive to IL10Rα deletion. Furthermore, single-cell transcriptomic analysis of adipose stromal populations identified lymphocytes as a key source of IL10 production in response to thermogenic stimuli. These findings implicate adaptive immune cell-adipocyte communication in the maintenance of adipose subtype identity and function.

Expression profiles and function of IL6 in polymorphonuclear myeloid-derived suppressor cells

2020 ◽  
Vol 69 (11) ◽  
pp. 2233-2245
Author(s):  
Mohammed L. Ibrahim ◽  
Chunwan Lu ◽  
John D. Klement ◽  
Priscilla S. Redd ◽  
Dafeng Yang ◽  
...  
Keyword(s):  
Expression Profiles ◽  
Suppressor Cells ◽  
Myeloid Derived Suppressor Cells ◽  
And Function

Myeloid-derived suppressor cells contribute to systemic lupus erythaematosus by regulating differentiation of Th17 cells and Tregs

2016 ◽  
Vol 130 (16) ◽  
pp. 1453-1467 ◽  
Author(s):  
Jianjian Ji ◽  
Jingjing Xu ◽  
Shuli Zhao ◽  
Fei Liu ◽  
Jingjing Qi ◽  
...  
Keyword(s):  
Disease Activity ◽  
Th17 Cell ◽  
Th17 Cells ◽  
Suppressor Cells ◽  
Cell Polarization ◽  
High Disease Activity ◽  
Myeloid Derived Suppressor Cells ◽  
Systemic Lupus ◽  
And Function

Although major advancements have made in investigating the aetiology of SLE (systemic lupus erythaematosus), the role of MDSCs (myeloid-derived suppressor cells) in SLE progression remains confused. Recently, some studies have revealed that MDSCs play an important role in lupus mice. However, the proportion and function of MDSCs in lupus mice and SLE patients are still poorly understood. In the present study, we investigated the proportion and function of MDSCs using different stages of MRL/lpr lupus mice and specimens from SLE patients with different activity. Results showed that splenic granulocytic (G-)MDSCs were significantly expanded by increasing the expression of CCR1 (CC chemokine receptor 1) in diseased MRL/lpr lupus mice and in high-disease-activity SLE patients. However, the proportion of monocytic (M-)MDSCs remains similar in MRL/lpr lupus mice and SLE patients. G-MDSCs produce high levels of ROS (reactive oxygen species) through increasing gp91phox expression, and activated TLR2 (Toll-like receptor 2) and AIM2 (absent in melanoma 2) inflammasome in M-MDSCs lead to IL-1β (interleukin 1β) expression in diseased MRL/lpr mice and high-disease-activity SLE patients. Previous study has revealed that MDSCs could alter the plasticity of Th17 (T helper 17) cells and Tregs (regulatory T-cells) via ROS and IL-1β. Co-culture experiments showed that G-MDSCs impaired Treg differentiation via ROS and M-MDSCs promoted Th17 cell polarization by IL-1β in vitro. Furthermore, adoptive transfer or antibody depletion of MDSCs in MRL/lpr mice confirmed that MDSCs influenced the imbalance of Tregs and Th17 cells in vivo. Our results indicate that MDSCs with the capacity to regulate Th17 cell/Treg balance may be a critical pathogenic factor in SLE.

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