Macrophages and microglia can be polarized along a continuum toward a detrimental (M1) or a beneficial (M2) state in the injured CNS. Although phagocytosis of myelin in vitro promotes M2 ...polarization, macrophage/microglia in the injured spinal cord retain a predominantly M1 state that is detrimental to recovery. We have identified two factors that underlie this skewing toward M1 polarization in the injured CNS. We show that TNF prevents phagocytosis-mediated conversion from M1 to M2 cells in vitro and in vivo in spinal cord injury (SCI). Additionally, iron that accumulates in macrophages in SCI increases TNF expression and the appearance of a macrophage population with a proinflammatory mixed M1/M2 phenotype. In addition, transplantation experiments show that increased loading of M2 macrophages with iron induces a rapid switch from M2 to M1 phenotype. The combined effect of this favors predominant and prolonged M1 macrophage polarization that is detrimental to recovery after SCI.
•Proinflammatory M1 macrophage polarization predominates in the injured spinal cord•TNF and iron regulate maintenance of such M1 polarization•TNF prevents myelin phagocytosis-induced conversion of M1 to prorepair M2 cells•Iron induces TNF expression and conversion from M2 to M1 cells
Macrophages and microglia can be polarized to a detrimental (M1) or a beneficial (M2) state. In the injured spinal cord these cells are predominantly polarized toward an M1 phenotype. Kroner et al. show that TNF and iron in the injured cord induce M1 polarization that is detrimental to recovery.
Osteoblasts, which are bone-forming cells, play pivotal roles in bone modeling and remodeling. Osteoblast differentiation, also known as osteoblastogenesis, is orchestrated by transcription factors, ...such as runt-related transcription factor 1/2, osterix, activating transcription factor 4, special AT-rich sequence-binding protein 2 and activator protein-1. Osteoblastogenesis is regulated by a network of cytokines under physiological and pathophysiological conditions. Osteoblastogenic cytokines, such as interleukin-10 (IL-10), IL-11, IL-18, interferon-γ (IFN-γ), cardiotrophin-1 and oncostatin M, promote osteoblastogenesis, whereas anti-osteoblastogenic cytokines, such as tumor necrosis factor-α (TNF-α), TNF-β, IL-1α, IL-4, IL-7, IL-12, IL-13, IL-23, IFN-α, IFN-β, leukemia inhibitory factor, cardiotrophin-like cytokine, and ciliary neurotrophic factor, downregulate osteoblastogenesis. Although there are gaps in the body of knowledge regarding the interplay of cytokine networks in osteoblastogenesis, cytokines appear to be potential therapeutic targets in bone-related diseases. Thus, in this study, we review and discuss our osteoblast, osteoblast differentiation, osteoblastogenesis, cytokines, signaling pathway of cytokine networks in osteoblastogenesis.
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•Sepsis infects more than 48.9 million people world-wide, with 19.7 million deaths.•Cytokine storm plays a significant role in sepsis, along with severe COVID-19.•TLR signaling ...pathways plays a crucial role in generating the cytokine storm.•Endogenous negative regulators of TLR signaling are crucial to regulate cytokine storm.
Cytokine storm generates during various systemic acute infections, including sepsis and current pandemic called COVID-19 (severe) causing devastating inflammatory conditions, which include multi-organ failure or multi-organ dysfunction syndrome (MODS) and death of the patient. Toll-like receptors (TLRs) are one of the major pattern recognition receptors (PRRs) expressed by immune cells as well as non-immune cells, including neurons, which play a crucial role in generating cytokine storm. They recognize microbial-associated molecular patterns (MAMPs, expressed by pathogens) and damage or death-associate molecular patterns (DAMPs; released and/expressed by damaged/killed host cells). Upon recognition of MAMPs and DAMPs, TLRs activate downstream signaling pathways releasing several pro-inflammatory mediators cytokines, chemokines, interferons, and reactive oxygen and nitrogen species (ROS or RNS), which cause acute inflammation meant to control the pathogen and repair the damage. Induction of an exaggerated response due to genetic makeup of the host and/or persistence of the pathogen due to its evasion mechanisms may lead to severe systemic inflammatory condition called sepsis in response to the generation of cytokine storm and organ dysfunction. The activation of TLR-induced inflammatory response is hardwired to the induction of several negative feedback mechanisms that come into play to conclude the response and maintain immune homeostasis. This state-of-the-art review describes the importance of TLR signaling in the onset of the sepsis-associated cytokine storm and discusses various host-derived endogenous negative regulators of TLR signaling pathways. The subject is very important as there is a vast array of genes and processes implicated in these negative feedback mechanisms. These molecules and mechanisms can be targeted for developing novel therapeutic drugs for cytokine storm-associated diseases, including sepsis, severe COVID-19, and other inflammatory diseases, where TLR-signaling plays a significant role.
The cytokine IL-10 is a key anti-inflammatory mediator ensuring protection of a host from over-exuberant responses to pathogens and microbiota, while playing important roles in other settings as ...sterile wound healing, autoimmunity, cancer, and homeostasis. Here we discuss our current understanding of the regulation of IL-10 production and of the molecular pathways associated with IL-10 responses. In addition to IL-10's classic inhibitory effects on myeloid cells, we also describe the nonclassic roles attributed to this pleiotropic cytokine, including how IL-10 regulates basic processes of neural and adipose cells and how it promotes CD8 T cell activation, as well as epithelial repair. We further discuss its therapeutic potential in the context of different diseases and the outstanding questions that may help develop an effective application of IL-10 in diverse clinical settings.
Background Studies suggest that inflammation is involved in the neurodegenerative cascade leading to Alzheimer's disease (AD) pathology and symptoms. This study sought to quantitatively summarize the ...clinical cytokine data. Methods Original English language peer-reviewed studies measuring cytokine concentrations in AD and healthy control subjects were included. Mean (±standard deviation) cytokine concentrations for AD and control subjects were extracted. Results Forty studies measuring peripheral blood cytokine concentrations and 14 measuring cerebrospinal fluid (CSF) cytokine concentrations were included. In peripheral blood, there were significantly higher concentrations (weighted mean difference 95% confidence interval) of interleukin (IL)-6 (2.86 1.68, 4.04 pg/mL, p < .00001, N AD/control subjects = 985/680, 14 studies), tumor necrosis factor (TNF)-α (3.25 .76, 5.74 pg/mL, p = .01, N = 680/447, 14 studies), IL-1β (.55 .32, .78 pg/mL, p < .00001, N = 574/370, 10 studies), transforming growth factor (TGF)-β (67.23 28.62, 105.83 pg/mL, p = .0006, N = 190/158, 5 studies), IL-12 (7.60 5.58, 9.62 pg/mL, p < .00001, N = 148/106, 5 studies), and IL-18 (15.82 1.98, 29.66 pg/mL, p = .03, N = 131/94, 4 studies) but not of IL-4, IL-8, IL-10, interferon-γ, or C-reactive protein in AD subjects compared with control subjects. There were significantly higher concentrations of TGF-β (7.81 2.27, 13.35 pg/mL, p =.006, N = 113/114, 5 studies) but not IL-6, TNF-α, and IL-1β in the CSF of AD subjects compared with control subjects. Conclusions These results strengthen the clinical evidence that AD is accompanied by an inflammatory response, particularly higher peripheral concentrations of IL-6, TNF-α, IL-1β, TGF-β, IL-12 and IL-18 and higher CSF concentrations of TGF-β.
Insufficient eradication capacity and dysfunction are common occurrences in T cells that characterize cancer immunotherapy failure. De novo DNA methylation promotes T cell exhaustion, whereas ...methylation inhibition enhances T cell rejuvenation in vivo. Decitabine, a DNA methyltransferase inhibitor approved for clinical use, may provide a means of modifying exhaustion-associated DNA methylation programmes. Herein, anti-tumour activities, cytokine production, and proliferation are enhanced in decitabine-treated chimeric antigen receptor T (dCAR T) cells both in vitro and in vivo. Additionally, dCAR T cells can eradicate bulky tumours at a low-dose and establish effective recall responses upon tumour rechallenge. Antigen-expressing tumour cells trigger higher expression levels of memory-, proliferation- and cytokine production-associated genes in dCAR T cells. Tumour-infiltrating dCAR T cells retain a relatively high expression of memory-related genes and low expression of exhaustion-related genes in vivo. In vitro administration of decitabine may represent an option for the generation of CAR T cells with improved anti-tumour properties.
Endosomal Toll-like receptors (TLRs) 7 and 9 recognize viral pathogens and induce signals leading to the activation of nuclear factor κB (NF-κB)-dependent proinflammatory cytokines and interferon ...regulatory factor 7 (IRF7)-dependent type I interferons (IFNs). Recognition of viral nucleic acids by TLR9 requires its cleavage in the endolysosomal compartment. Here, we show that TLR9 signals leading to the activation of type I IFN, but not proinflammatory cytokine genes, require TLR9 trafficking from endosomes to a specialized lysosome-related organelle. Furthermore, we identify adapter protein-3 as the protein complex responsible for the trafficking of TLR9 to this subcellular compartment. Our results reveal an intracellular mechanism for bifurcation of TLR9 signals by selective receptor trafficking within the endosomal system.
Background Cytokines are well-known immunomodulators. Thanks to recent success of immune checkpoint inhibitors there is a renewed interest in cytokines as a promising cancer immunotherapy option. ...Several inflammatory cytokines including IL-12 showed potent anti-tumor activities but severe immune adverse events when administered systemically greatly hindered using them as anti-tumor agents. Methods Previously (SITC 2020) we showed that IL-12 activity was reduced by our introduced mutation (termed as mut1) if measured by pSTAT4 AlphaLISA assay. But when it was treated in human immune cells IFNg production was not reduced as expected. Thus, we further attenuated IL-12 activities by protein engineering and created our candidate molecule KNP-101. Results We showed that KNP-101 maintained potent anti-tumor activities in vivo but gained greatly improved toxicity profiles. When we measured pSTAT4 signals, KNP-101 showed about 30-fold attenuation in IL-12 activities compared with rIL-12. IFNg production from human PBMC was also reduced. Although the IL-12 activity was weakened in order to reduce its systemic toxicity, our KNP-101 mouse surrogate still maintained good anti-tumor potency in various mouse syngeneic models with a single intravenous injection as low as 2 ug/head. In combination with anti-PD-L1, KNP-101 surrogate showed a synergistic anti-tumor effect and further FACS analysis of tumor infiltrated lymphocytes demonstrated that the effects were mediated by immune cell infiltration. Importantly, in CD1 naïve mouse toxicity test, KNP-101 surrogate was tolerable up to 50 ug/head and no survival issue was observed. However, that was not the case with the control group, non-tumor-targeting null/IL-12 showing survival issues with all tested dose levels. Compared with the control, KNP-101 surrogate also showed much safer profiles in terms of organ weight and serum chemistry such as ALT level. We also performed similar toxicity study in tumor-bearing mice. KNP-101 surrogate again showed a very safe profiles being tolerable up to 500 ug/head and no survival issue. Noticeably, when serum IFNg was measured in tumor-bearing mice, our KNP-101 surrogate induced far less IFNg in serum compared to null/IL-12 suggesting that systemic toxicity was greatly reduced. Conclusions Together, we demonstrated that systemic toxicity of IL-12 cytokine therapy can be overcome by tumor-targeting and IL-12 attenuation. Our KNP-101 has a widen therapeutic window by maintaining potent anti-tumor activities and showing much improved safety profiles. We hope that KNP-101 can benefit patients in the future who suffer from primary and acquired resistance of the current anti-PD-1/PD-L1 treatments.
BackgroundTumor-specific CD8+ T-cells play a critical role in tumor control, as demonstrated by the success of immune checkpoint inhibitors and adoptive cell therapy. Studies of mice and human ...tumor-infiltrating lymphocytes (TILs) demonstrate that tumor-specific CD8+ TILs can be defined by CD39 expression on their surface. CD39 is commonly considered an immunosuppressive enzyme, as it depletes ATP. However, CD39 is also associated with mitigating activation-induced cell death and mediating leukocyte trafficking. It is, however, unclear whether CD39 expression on tumor-specific T-cells can be regulated by putative anti-tumor factors such as pro-inflammatory cytokines similar to the phenotype and anti-tumor properties of CD8+ TILs. IL-12 and IL-27 have established roles in promoting effector T-cell differentiation, expansion, and cytotoxic activity. Both cytokines are implicated in the upregulation of CD39 by T regulatory cells, suggesting they may regulate CD39 expression in other cell types, including tumor-specific CD8+ T-cells. We hypothesize that IL-12 and IL-27 induce CD39 upregulation on CD8+ T- cells, modulating their anti-tumor properties.MethodsAn engineered immunogenic, syngeneic neuroblastoma (neuro-2a) mouse model was used for in vitro and in vivo experiments. CD8+ T-cells or bulk splenocytes isolated from naïve or neuro-2a vaccinated mice were stimulated in vitro using anti-CD3/CD28 Dynabeads and IL-2 ± IL-12 or IL-27. Flow cytometry was used to determine the phenotype of CD8+ T-cells and assess effector activity. Additionally, we inhibited IL-12 activity in vivo to study the effect on CD8+ TIL expression of CD39. An isotype control antibody was administered to a separate group to act as a control.ResultsOur in vitro results demonstrate that CD8+ T-cells stimulated in the presence of IL-12 or IL-27 had higher expression of CD39 compared to stimulated controls. In addition, we found a higher frequency of CD39+CD8+ T-cells expressing IFNγ and CD107a than CD39- counterparts. Finally, blocking IL-12 activity in vivo reduced CD39+CD8+ TIL frequency compared to the isotype control group.ConclusionsOur results establish that IL-12 and IL-27 induce CD39 expression on CD8+ T-cells and blocking IL-12 reduced CD39+CD8+ TIL frequency. Furthermore, CD39 expression is associated with improved effector CD8+ T-cell function. Future experiments will assess the functionality of CD39+CD8+ T-cells using ex vivo cytotoxicity assays. Data generated in this study will provide novel information on the mechanism of CD39 induction and its effect on CD8+ T-cell function, which can be exploited to improve future cancer therapies.
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