scholarly journals Macrophages and Dendritic Cells Are Not the Major Source of Pro-Inflammatory Cytokines Upon SARS-CoV-2 Infection

2021 ◽  
Vol 12 ◽  
Author(s):  
Marc A. Niles ◽  
Patricia Gogesch ◽  
Stefanie Kronhart ◽  
Samira Ortega Iannazzo ◽  
Georg Kochs ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Inflammatory Cytokines ◽  
Immune Cells ◽  
Influenza A ◽  
Innate Immune ◽  
Innate Immune Cells ◽  
M2 Macrophages ◽  
Myeloid Dendritic Cells ◽  
M1 And M2 Macrophages ◽  
Pro Inflammatory Cytokines

The exact role of innate immune cells upon infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and their contribution to the formation of the corona virus-induced disease (COVID)-19 associated cytokine storm is not yet fully understood. We show that human in vitro differentiated myeloid dendritic cells (mDC) as well as M1 and M2 macrophages are susceptible to infection with SARS-CoV-2 but are not productively infected. Furthermore, infected mDC, M1-, and M2 macrophages show only slight changes in their activation status. Surprisingly, none of the infected innate immune cells produced the pro-inflammatory cytokines interleukin (IL)−6, tumor necrosis factor (TNF)-α, or interferon (IFN)−α. Moreover, even in co-infection experiments using different stimuli, as well as non-influenza (non-flu) or influenza A (flu) viruses, only very minor IL-6 production was induced. In summary, we conclude that mDC and macrophages are unlikely the source of the first wave of cytokines upon infection with SARS-CoV-2.

Cytokine networking of innate immunity cells: a potential target of therapy

2014 ◽  
Vol 126 (9) ◽  
pp. 593-612 ◽  
Author(s):  
Ilja Striz ◽  
Eva Brabcova ◽  
Libor Kolesar ◽  
Alena Sekerkova
Keyword(s):  
T Cells ◽  
Epithelial Cells ◽  
Regulatory T Cells ◽  
Inflammatory Cytokines ◽  
Immune Cells ◽  
Innate Immune ◽  
Lymphoid Cells ◽  
Extracellular Matrix Protein ◽  
Innate Immune Cells ◽  
Pro Inflammatory Cytokines

Innate immune cells, particularly macrophages and epithelial cells, play a key role in multiple layers of immune responses. Alarmins and pro-inflammatory cytokines from the IL (interleukin)-1 and TNF (tumour necrosis factor) families initiate the cascade of events by inducing chemokine release from bystander cells and by the up-regulation of adhesion molecules required for transendothelial trafficking of immune cells. Furthermore, innate cytokines produced by dendritic cells, macrophages, epithelial cells and innate lymphoid cells seem to play a critical role in polarization of helper T-cell cytokine profiles into specific subsets of Th1/Th2/Th17 effector cells or regulatory T-cells. Lastly, the innate immune system down-regulates effector mechanisms and restores homoeostasis in injured tissue via cytokines from the IL-10 and TGF (transforming growth factor) families mainly released from macrophages, preferentially the M2 subset, which have a capacity to induce regulatory T-cells, inhibit the production of pro-inflammatory cytokines and induce healing of the tissue by regulating extracellular matrix protein deposition and angiogenesis. Cytokines produced by innate immune cells represent an attractive target for therapeutic intervention, and multiple molecules are currently being tested clinically in patients with inflammatory bowel disease, rheumatoid arthritis, systemic diseases, autoinflammatory syndromes, fibrosing processes or malignancies. In addition to the already widely used blockers of TNFα and the tested inhibitors of IL-1 and IL-6, multiple therapeutic molecules are currently in clinical trials targeting TNF-related molecules [APRIL (a proliferation-inducing ligand) and BAFF (B-cell-activating factor belonging to the TNF family)], chemokine receptors, IL-17, TGFβ and other cytokines.

scholarly journals Immunoporosis: Role of Innate Immune Cells in Osteoporosis

2021 ◽  
Vol 12 ◽  
Author(s):  
Yogesh Saxena ◽  
Sanjeev Routh ◽  
Arunika Mukhopadhaya
Keyword(s):  
Inflammatory Cytokines ◽  
Immune Cells ◽  
Inflammatory Mediators ◽  
Innate Immune ◽  
Innate Immune Cells ◽  
Myeloid Lineage ◽  
Molecular Patterns ◽  
The Impact ◽  
Pro Inflammatory Cytokines

Osteoporosis or porous bone disorder is the result of an imbalance in an otherwise highly balanced physiological process known as ‘bone remodeling’. The immune system is intricately involved in bone physiology as well as pathologies. Inflammatory diseases are often correlated with osteoporosis. Inflammatory mediators such as reactive oxygen species (ROS), and pro-inflammatory cytokines and chemokines directly or indirectly act on the bone cells and play a role in the pathogenesis of osteoporosis. Recently, Srivastava et al. (Srivastava RK, Dar HY, Mishra PK. Immunoporosis: Immunology of Osteoporosis-Role of T Cells. Frontiers in immunology. 2018;9:657) have coined the term “immunoporosis” to emphasize the role of immune cells in the pathology of osteoporosis. Accumulated pieces of evidence suggest both innate and adaptive immune cells contribute to osteoporosis. However, innate cells are the major effectors of inflammation. They sense various triggers to inflammation such as pathogen-associated molecular patterns (PAMPs), damage-associated molecular patterns (DAMPs), cellular stress, etc., thus producing pro-inflammatory mediators that play a critical role in the pathogenesis of osteoporosis. In this review, we have discussed the role of the innate immune cells in great detail and divided these cells into different sections in a systemic manner. In the beginning, we talked about cells of the myeloid lineage, including macrophages, monocytes, and dendritic cells. This group of cells explicitly influences the skeletal system by the action of production of pro-inflammatory cytokines and can transdifferentiate into osteoclast. Other cells of the myeloid lineage, such as neutrophils, eosinophils, and mast cells, largely impact osteoporosis via the production of pro-inflammatory cytokines. Further, we talked about the cells of the lymphoid lineage, including natural killer cells and innate lymphoid cells, which share innate-like properties and play a role in osteoporosis. In addition to various innate immune cells, we also discussed the impact of classical pro-inflammatory cytokines on osteoporosis. We also highlighted the studies regarding the impact of physiological and metabolic changes in the body, which results in chronic inflammatory conditions such as ageing, ultimately triggering osteoporosis.

scholarly journals Recent insights into the implications of metabolism in plasmacytoid dendritic cell innate functions: Potential ways to control these functions

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 456 ◽  
Author(s):  
Philippe Saas ◽  
Alexis Varin ◽  
Sylvain Perruche ◽  
Adam Ceroi
Keyword(s):  
Dendritic Cells ◽  
Lipid Metabolism ◽  
Nuclear Receptors ◽  
Immune Cells ◽  
Transforming Growth Factor ◽  
Plasmacytoid Dendritic Cell ◽  
Innate Immune ◽  
Type I ◽  
Innate Immune Cells ◽  
Immune Functions

There are more and more data concerning the role of cellular metabolism in innate immune cells, such as macrophages or conventional dendritic cells. However, few data are available currently concerning plasmacytoid dendritic cells (PDC), another type of innate immune cells. These cells are the main type I interferon (IFN) producing cells, but they also secrete other pro-inflammatory cytokines (e.g., tumor necrosis factor or interleukin [IL]-6) or immunomodulatory factors (e.g., IL-10 or transforming growth factor-β). Through these functions, PDC participate in antimicrobial responses or maintenance of immune tolerance, and have been implicated in the pathophysiology of several autoimmune diseases. Recent data support the idea that the glycolytic pathway (or glycolysis), as well as lipid metabolism (including both cholesterol and fatty acid metabolism) may impact some innate immune functions of PDC or may be involved in these functions after Toll-like receptor (TLR) 7/9 triggering. Some differences may be related to the origin of PDC (human versus mouse PDC or blood-sorted versus FLT3 ligand stimulated-bone marrow-sorted PDC). The kinetics of glycolysis may differ between human and murine PDC. In mouse PDC, metabolism changes promoted by TLR7/9 activation may depend on an autocrine/paracrine loop, implicating type I IFN and its receptor IFNAR, explaining a delayed glycolysis. Moreover, PDC functions can be modulated by the metabolism of cholesterol and fatty acids. This may occur via the production of lipid ligands that activate nuclear receptors (e.g., liver X receptor [LXR]) in PDC or through limiting intracellular cholesterol pool size (by statins or LXR agonists) in these cells. Finally, lipid-activated nuclear receptors (i.e., LXR or peroxisome proliferator activated receptor) may also directly interact with pro-inflammatory transcription factors, such as NF-κB. Here, we discuss how glycolysis and lipid metabolism may modulate PDC functions and how this may be harnessed in pathological situations where PDC play a detrimental role.

scholarly journals Natural Killer Dendritic Cells Enhance Immune Responses Elicited byα-Galactosylceramide-Stimulated Natural Killer T Cells

2013 ◽  
Vol 2013 ◽  
pp. 1-18 ◽  
Author(s):  
Sung Won Lee ◽  
Hyun Jung Park ◽  
Nayoung Kim ◽  
Seokmann Hong
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Immune Responses ◽  
Natural Killer ◽  
Immune Cells ◽  
Tumor Antigens ◽  
Nkt Cells ◽  
Innate Immune ◽  
Innate Immune Cells ◽  
Natural Killer T

Natural killer dendritic cells (NKDCs) possess potent anti-tumor activity, but the cellular effect of NKDC interactions with other innate immune cells is unclear. In this study, we demonstrate that the interaction of NKDCs and natural killer T (NKT) cells is required for the anti-tumor immune responses that are elicited byα-galactosylceramide (α-GC) in mice. The rapid and strong expression of interferon-γby NKDCs afterα-GC stimulation was dependent on NKT cells. Various NK and DC molecular markers and cytotoxic molecules were up-regulated followingα-GC administration. This up-regulation could improve NKDC presentation of tumor antigens and increase cytotoxicity against tumor cells. NKDCs were required for the stimulation of DCs, NK cells, and NKT cells. The strong anti-tumor immune responses elicited byα-GC may be due to the down-regulation of regulatory T cells. Furthermore, the depletion of NKDCs dampened the tumor clearance mediated byα-GC-stimulated NKT cellsin vivo. Taken together, these results indicate that complex interactions of innate immune cells might be required to achieve optimal anti-tumor immune responses during the early stages of tumorigenesis.

Calreticulin Promotes Immunity Against Acute Myeloid Leukemia Cells in Vivo

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 996-996
Author(s):  
Xiufen Chen ◽  
Dominick Fosco ◽  
Douglas E. Kline ◽  
Justin Kline
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Cell Surface ◽  
Vector Control ◽  
Immune Cells ◽  
Myeloid Leukemia ◽  
Innate Immune ◽  
Innate Immune Cells

Abstract Pre-apoptotic cancer cells release internalized calreticulin (CRT) to their surface prior to death, which acts as an ‘eat-me’ signal to local phagocytes. Chemotherapy and irradiation, which can induce immunogenic cell death through CRT translocation, can also result in local and/or systemic immune suppression in the host. To bypass the requirement of exposing the host to chemotherapy to induce translocation of CRT to the cell surface, murine acute myeloid leukemia (AML) cells (C1498), were engineered to constitutively express cell surface CRT (C1498.CRT). Vector control C1498 or C1498.CRT cells were inoculated intravenously (IV) into C57BL/6 mice. Significantly prolonged survival was observed in hosts harboring C1498.CRT versus vector control C1498 cells systemically. The survival benefit were abrogated in both Rag2-/- hosts or by depletion of T cells with anti-CD4 plus anti-CD8 antibodies, arguing that the immune-mediated effect of cell-surface CRT expression is dependent upon a functional adaptive immune system. More strikingly, systemic inoculation with C1498.CRT cells expressing the model SIYRYYGL (SIY) peptide antigen (C1498.SIY.CRT cells) resulted in almost complete protection from AML development (>90% long term survival vs. 10% of C1498.SIY vector control cells). All animals surviving a primary C1498.SIY.CRT challenge rejected a subsequent re-challenge with C1498.SIY cells, suggesting that CRT-expressing AML cells promote immunologic memory. Significantly enhanced expansion and unregulated IFNγ production were observed among SIY-specific T cell receptor transgenic CD8+ 2C T cells following their adoptive transfer into hosts bearing C1498.SIY.CRT AML cells versus vector control C1498.SIY cells. Interestingly, CRT expression on AML cells did not promote their in vivo phagocytosis by innate immune cells, specifically splenic CD8a+ dendritic cells known to engulf AML cells following their IV inoculation. IL-12 production by CD8α+CD11c+ dendritic cells which had engulfed C1498 and C1498.CRT cells in vivo was similarly induced, and cross-presentation of the SIY antigen to 2C T cells ex vivo by purified CD8a+DCs following in vivo exposure to C1498.SIY or C1498.SIY.CRT cells was also similar. In conclusion, it is clear that expression on CRT on the surface of AML cells leads to robust leukemia-specific T cell activation and expansion resulting in prolonged leukemia-specific survival in AML-bearing animals. Although a direct effect of CRT on innate immune cells, such as dendritic cells, is suspected, the molecular mechanism underlying the “CRT effect” remains unclear, and is being explored further through gene expression analysis in purified DCs which have engulfed CRT-expressing or control AML cells in vivo, as well as in animals genetically deficient in the putative CRT receptor, LRP, in dendritic cells. It will be of interest to analyze spontaneous CRT expression on AML cells from human samples and to correlate cell surface CRT expression with the presence or absence of spontaneous T cell responses to known AML antigens and with clinical outcomes. Disclosures No relevant conflicts of interest to declare.

scholarly journals Interfering with MIF-CD74 signalling on macrophages and dendritic cells with a peptide-based approach restores the immune response against metastatic melanoma

2018 ◽  
Author(s):  
Carlos R. Figueiredo ◽  
Ricardo A. Azevedo ◽  
Sasha Mousdell ◽  
Pedro T. Resende-Lara ◽  
Lucy Ireland ◽  
...  
Keyword(s):  
Immune Response ◽  
Dendritic Cells ◽  
Metastatic Melanoma ◽  
Immune Cells ◽  
Tumour Microenvironment ◽  
Innate Immune ◽  
Innate Immune Cells ◽  
Adaptive Immune Cells ◽  
Cancer Immunotherapies

ABSTRACTMounting an effective immune response against cancer requires the activation of innate and adaptive immune cells. Metastatic melanoma is the most aggressive form of skin cancer. Immunotherapies that boost the activity of effector T cells have shown a remarkable success in melanoma treatment. Patients, however, can develop resistance to such therapies by mechanisms that include the establishment of an immune suppressive tumour microenvironment. Understanding how metastatic melanoma cells suppress the immune system is vital to develop effective immunotherapies against this disease. In this study, we find that the innate immune cells, macrophages and dendritic cells are suppressed in metastatic melanoma. The Ig-CDR-based peptide C36L1 is able to restore macrophages and dendritic cells’ immunogenic functions and to inhibit metastatic growth in vivo. Mechanistically, we found that C36L1 interferes with the MIF-CD74 tumour-innate immune cells immunosuppressive signalling pathway and thereby restores an effective anti-tumour immune response. C36L1 directly binds to CD74 on macrophages and dendritic cells, disturbing CD74 structural dynamics and inhibiting MIF signalling through CD74. Our findings suggest that interfering with MIF-CD74 immunosuppressive signalling in macrophages and dendritic cells using peptide-based immunotherapy can restore the anti-tumour immune response in metastatic melanoma. Our study provides the rationale for further development of peptide-based therapies to restore the anti-tumour immune response.

scholarly journals Effect of vitamin D on immune response of respiratory system against influenzas and COVID-19: A review

2020 ◽  
Vol 3 (6) ◽  
pp. 100
Author(s):  
Payam Hashemi ◽  
Hossein Mirmiranpour ◽  
Shaghayegh Pezeshki
Keyword(s):  
Vitamin D ◽  
Immune Cells ◽  
Viral Infections ◽  
Severe Pneumonia ◽  
Innate Immune ◽  
System Response ◽  
Innate Immune Cells ◽  
Immune System Response ◽  
Tract Infections ◽  
Pro Inflammatory Cytokines

Vitamin D could decrease the risk of viral infections with regulation of the immune system response against viral activity. Proper level of 25(OH)D decreases the risk of chronic respiratory tract infections (RTIs), malignancies, hypertension, cardiovascular disease, and diabetes mellitus. Vitamin D can decrease risk of RTIs through some mechanisms. Adequate levels of vitamin D can decrease the level of pro-inflammatory cytokines which predominantly release from innate immune cells. It also can preserve tight junctions in the base membrane. Vitamin D may eliminate enveloped viruses by activating cathelicidin (a protein in the membrane of neutrophils, macrophages, and epithelial cells). These processes can reduce the risk of a cytokine storm and severe pneumonia. Clinical trials have shown the beneficial influences of vitamin D in decreasing the risk of viral pneumonia, dengue fever, hepatitis B, hepatitis C, and herpes infections.Keywords: Vitamin D, influenza, covid-19, innate immune cells, infections

scholarly journals Immunohistochemical Study of ASC Expression and Distribution in the Hippocampus of an Aged Murine Model of Alzheimer’s Disease

2021 ◽  
Vol 22 (16) ◽  
pp. 8697
Author(s):  
Diana Reimers ◽  
Manuela Vallejo-Muñoz ◽  
María José Casarejos ◽  
Adriano Jimenez-Escrig ◽  
Rafael Gonzalo-Gobernado ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Immune Cells ◽  
Immunohistochemical Study ◽  
Transgenic Mouse Model ◽  
Innate Immune ◽  
Innate Immune Cells ◽  
Danger Signals ◽  
Model Of Alzheimer’S Disease ◽  
Pro Inflammatory Cytokines

Neuroinflammation is involved in the pathogenesis of neurodegenerative diseases such as Alzheimer’s disease (AD), and is notably dependent on age. One important inflammatory pathway exerted by innate immune cells of the nervous system in response to danger signals is mediated by inflammasomes (IF) and leads to the generation of potent pro-inflammatory cytokines. The protein “apoptosis-associated speck-like protein containing a caspase recruitment domain” (ASC) modulates IF activation but has also other functions which are crucial in AD. We intended to characterize immunohistochemically ASC and pattern recognition receptors (PRR) of IF in the hippocampus (HP) of the transgenic mouse model Tg2576 (APP), in which amyloid-beta (Aβ) pathology is directly dependent on age. We show in old-aged APP a significant amount of ASC in microglia and astrocytes associated withAβ plaques, in the absence of PRR described by others in glial cells. In addition, APP developed foci with clusters of extracellular ASC granules not spatiallyrelated to Aβ plaques, which density correlated with the advanced age of mice and AD development. Clusters were associated withspecific astrocytes characterized by their enlarged ring-shaped process terminals, ASC content, and frequent perivascular location. Their possible implication in ASC clearance and propagation of inflammation is discussed.

scholarly journals Regulation of Hierarchical Clustering and Activation of Innate Immune Cells by Dendritic Cells

Immunity ◽  
2008 ◽  
Vol 29 (5) ◽  
pp. 819-833 ◽  
Author(s):  
Suk-Jo Kang ◽  
Hong-Erh Liang ◽  
Boris Reizis ◽  
Richard M. Locksley
Keyword(s):  
Dendritic Cells ◽  
Hierarchical Clustering ◽  
Immune Cells ◽  
Innate Immune ◽  
Innate Immune Cells

scholarly journals Tubular lysosome biogenesis in innate immune cells

2021 ◽  
Author(s):  
Amra Saric
Keyword(s):  
Dendritic Cells ◽  
Antigen Presentation ◽  
Immune Cells ◽  
Cell Function ◽  
Fluid Phase ◽  
Adaptor Proteins ◽  
Innate Immune ◽  
Innate Immune Cells ◽  
Lysosome Biogenesis ◽  
Dynamic Structures

Lysosomes are essential organelles required for breakdown of endocytic and biosynthetic cargo, pathogen killing and autophagy. In most cells, lysosomes are typically small punctate structures. By contrast, innate immune cells like macrophages and dendeitic cells that have been exposed to bacterial lipopolysaccharids (LPS) exhibit strikingly tubular lysosomes (TLs) and lysosome-related major histocompatility class II (MHCII) compartments (MIIC), respectively. TLs are suggested to play a role in phagosome maturation and retention of fluid-phase endocytic uptake in activated macrophages. In addition, the dendritic cell tubular MIIC (tMIIC) may be involved in antigen presentation. Since remarkably little was known about how tubular lysosomes form, I took to investigate the molecular requirements for this process in macrophages and dendritic cells and present my findings in this thesis. Here I confirm that microtubules are necessary as a template for lysosome tabulation, along with dynein and kinesin microtubule-dependendent motors. We were first to identify molecular components necessary for lysosome tabulation; TL biogenesis required the concerted action of the Ar18b GTPasem along with its effector SKIP, a kinesin adaptor proteins for dynein and kinesin, respectively. Importantly, we observed that TLs are highly dynamic structures whereas punctate lysosomes are conspicuously more static. I also present evidence that mTOR, a lysosomal protein kinase, is required for LPS-induced TL biogenesis and cell surface delivery of MHCII in macrophages and dendritic cells. First, I show that the MyD88-P13K-Akt-mTOR signaling pathway regulates LPS-induced lysosome tabulation. Second, I demonstrate that mTOR is required for anterograde lysosomal transport suggesting that this kinase may regulate tabulation and antigen presentation by modulating the microtubule-based motor activity of lysosomes. Finally I present preliminary data on the properties of tubular lysosomes compare to punctate lysosomes in an effort to characterize these organelles. Among the data presented is evidence that total lysosomal volume increases significantly upon tabulation, which may have important underlying implications in antigen sampling and processing. Overall, my work has expanded on our knowledge on our knowledge of how morphology and trafficking of lysosomes is modulated in immune cells, which may alter cell function.

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