scholarly journals Journey to the Center of the Cell: Cytoplasmic and Nuclear Actin in Immune Cell Functions

Author(s):  
Julien Record ◽  
Mezida B. Saeed ◽  
Tomas Venit ◽  
Piergiorgio Percipalle ◽  
Lisa S. Westerberg

Actin cytoskeletal dynamics drive cellular shape changes, linking numerous cell functions to physiological and pathological cues. Mutations in actin regulators that are differentially expressed or enriched in immune cells cause severe human diseases known as primary immunodeficiencies underscoring the importance of efficienct actin remodeling in immune cell homeostasis. Here we discuss recent findings on how immune cells sense the mechanical properties of their environement. Moreover, while the organization and biochemical regulation of cytoplasmic actin have been extensively studied, nuclear actin reorganization is a rapidly emerging field that has only begun to be explored in immune cells. Based on the critical and multifaceted contributions of cytoplasmic actin in immune cell functionality, nuclear actin regulation is anticipated to have a large impact on our understanding of immune cell development and functionality.

2020 ◽  
Vol 21 (23) ◽  
pp. 8929
Author(s):  
Melanie Kienzl ◽  
Julia Kargl ◽  
Rudolf Schicho

Leukocytes are part of the tumor microenvironment (TME) and are critical determinants of tumor progression. Because of the immunoregulatory properties of cannabinoids, the endocannabinoid system (ECS) may have an important role in shaping the TME. Members of the ECS, an entity that consists of cannabinoid receptors, endocannabinoids and their synthesizing/degrading enzymes, have been associated with both tumor growth and rejection. Immune cells express cannabinoid receptors and produce endocannabinoids, thereby forming an “immune endocannabinoid system”. Although in vitro effects of exogenous cannabinoids on immune cells are well described, the role of the ECS in the TME, and hence in tumor development and immunotherapy, is still elusive. This review/opinion discusses the possibility that the “immune endocannabinoid system” can fundamentally influence tumor progression. The widespread influence of cannabinoids on immune cell functions makes the members of the ECS an interesting target that could support immunotherapy.


2020 ◽  
Vol 8 (24) ◽  
pp. 5195-5203
Author(s):  
Joslyn L. Mangal ◽  
Sahil Inamdar ◽  
Yi Yang ◽  
Subhadeep Dutta ◽  
Mamta Wankhede ◽  
...  

Metabolites control immune cell functions, and delivery of these metabolites in a sustained manner modulate the function of the immune cells.


2012 ◽  
Vol 23 (23) ◽  
pp. 4567-4578 ◽  
Author(s):  
Christopher M. Groen ◽  
Andrew J. Spracklen ◽  
Tiffany N. Fagan ◽  
Tina L. Tootle

Although prostaglandins (PGs)—lipid signals produced downstream of cyclooxygenase (COX) enzymes—regulate actin cytoskeletal dynamics, their mechanisms of action are unknown. We previously established Drosophila oogenesis, in particular nurse cell dumping, as a new model to determine how PGs regulate actin remodeling. PGs, and thus the Drosophila COX-like enzyme Pxt, are required for both the parallel actin filament bundle formation and the cortical actin strengthening required for dumping. Here we provide the first link between Fascin (Drosophila Singed, Sn), an actin-bundling protein, and PGs. Loss of either pxt or fascin results in similar actin defects. Fascin interacts, both pharmacologically and genetically, with PGs, as reduced Fascin levels enhance the effects of COX inhibition and synergize with reduced Pxt levels to cause both parallel bundle and cortical actin defects. Conversely, overexpression of Fascin in the germline suppresses the effects of COX inhibition and genetic loss of Pxt. These data lead to the conclusion that PGs regulate Fascin to control actin remodeling. This novel interaction has implications beyond Drosophila, as both PGs and Fascin-1, in mammalian systems, contribute to cancer cell migration and invasion.


2021 ◽  
Vol 22 (13) ◽  
pp. 6818
Author(s):  
Masato Mashimo ◽  
Yasuhiro Moriwaki ◽  
Hidemi Misawa ◽  
Koichiro Kawashima ◽  
Takeshi Fujii

Acetylcholine (ACh) is the classical neurotransmitter in the cholinergic nervous system. However, ACh is now known to regulate various immune cell functions. In fact, T cells, B cells, and macrophages all express components of the cholinergic system, including ACh, muscarinic, and nicotinic ACh receptors (mAChRs and nAChRs), choline acetyltransferase, acetylcholinesterase, and choline transporters. In this review, we will discuss the actions of ACh in the immune system. We will first briefly describe the mechanisms by which ACh is stored in and released from immune cells. We will then address Ca2+ signaling pathways activated via mAChRs and nAChRs on T cells and B cells, highlighting the importance of ACh for the function of T cells, B cells, and macrophages, as well as its impact on innate and acquired (cellular and humoral) immunity. Lastly, we will discuss the effects of two peptide ligands, secreted lymphocyte antigen-6/urokinase-type plasminogen activator receptor-related peptide-1 (SLURP-1) and hippocampal cholinergic neurostimulating peptide (HCNP), on cholinergic activity in T cells. Overall, we stress the fact that ACh does not function only as a neurotransmitter; it impacts immunity by exerting diverse effects on immune cells via mAChRs and nAChRs.


2020 ◽  
Vol 8 (S1) ◽  
Author(s):  
Xiaomin Zhang ◽  
Fabian Zink ◽  
Felix Hezel ◽  
Josef Vogt ◽  
Ulrich Wachter ◽  
...  

AbstractImmune cell activation leads to the acquisition of new functions, such as proliferation, chemotaxis, and cytokine production. These functional changes require continuous metabolic adaption in order to sustain ATP homeostasis for sufficient host defense. The bioenergetic demands are usually met by the interconnected metabolic pathways glycolysis, TCA cycle, and oxidative phosphorylation. Apart from glucose, other sources, such as fatty acids and glutamine, are able to fuel the TCA cycle.Rising evidence has shown that cellular metabolism has a direct effect on the regulation of immune cell functions. Thus, quiescent immune cells maintain a basal metabolic state, which shifts to an accelerated metabolic level upon immune cell activation in order to promote key effector functions.This review article summarizes distinct metabolic signatures of key immune cell subsets from quiescence to activation and demonstrates a methodical concept of how to assess cellular metabolic pathways. It further discusses why metabolic functions are of rising interest for translational research and how they can be affected by the underlying pathophysiological condition and/or therapeutic interventions.


2019 ◽  
Author(s):  
Michael H. Zhang ◽  
Emily M. Slaby ◽  
Georgina Stephanie ◽  
Chunsong Yu ◽  
Darcy M. Watts ◽  
...  

AbstractCell-based immunotherapies have tremendous potential to treat many diseases, such as activating immunity in cancer or suppressing it in autoimmune diseases. Most cell-based cancer immunotherapies in the clinic provide adjuvant signals through genetic engineering to enhance T cell functions. However, genetically encoded signals have minimal control over dosing and persist for the life of a cell lineage. These properties make it difficult to balance increasing therapeutic efficacy with reducing toxicities. Here, we demonstrated the potential of phospholipid-coupled ligands as a non-genetic system for immune cell engineering. This system provides simple, controlled, non-genetic adjuvant delivery to immune cells via lipid-mediated insertion into plasma membranes. Lipid-mediated insertion (depoting) successfully delivered Toll-like receptor (TLR) ligands intracellularly and onto cell surfaces of diverse immune cells. These ligands depoted into immune cells in a dose-controlled fashion and did not compete during multiplex pairwise loading. Immune cell activation could be enhanced by autocrine and paracrine mechanisms depending on the biology of the TLR ligand tested. We determined that depoted ligands can functionally persist on plasma membranes for up to four days in naïve and activated T cells, enhancing their activation, proliferation, and skewing cytokine secretion. Depoted ligands provide a persistent yet non-permanent adjuvant signal to immune cells that may minimize the intensity and duration of toxicities compared to permanent genetic delivery. Altogether, these findings demonstrate potential for lipid-mediated insertion (depoting) as a universal cell engineering approach with unique, complementary advantages to other cell engineering methods.


2021 ◽  
Author(s):  
Fangfang Li ◽  
Chun Huang ◽  
Llingxiao Qiu ◽  
Ping Li ◽  
Guojun Zhang

Abstract Purpose The immunotherapy of lung adenocarcinoma has received more and more attention. Different immune cells can affect other metabolic genes and lifespan, and cell metabolism directly regulates immune cell functions. Therefore, it is crucial to explore the role of immune-related metabolic genes in lung adenocarcinoma. Methods In this study, we divided immune-related metabolic genes into three categories based on different immune characteristics and researched immune and clinical pathology. LASSO regression analysis was used to screen immune-related metabolic genes, and a clinical prediction model of the screened genes was constructed. Finally, we selected the intersection of immune metabolism genes that are highly expressed in the tumor site and immune metabolism genes that are negatively related to survival, and used qRT-PCR for experimental verification. Results We first screened out immune-related metabolic genes that may affect lung cancer tumor progression, and screened out 9 pivot genes (TK1, TCN1, CAV1, ACMSD, HS3ST2, HS3ST5, AMN, ADRA2C, ACOXL) through LASSO regression analysis and constructed Prognosis model. Finally, through the screening of tumor-related immune metabolism genes, we obtained five pivot genes (HMMR, PFKP, RRM2, TCN1 and TK1). Our qRT-PCR results also show that RRM2 is positively correlated with CDK2, CDK4, CDK6, and CDK8, revealing the close relationship between RRM2 and immune cell tumor infiltration. Conclusion We conducted a comprehensive analysis of the immune infiltration of the tumor microenvironment of lung cancer, and finally determined RRM2 as a promising immune metabolism checkpoint for lung adenocarcinoma based on the high correlation of RRM2 with immune cells and CDK family.


2021 ◽  
Vol 12 ◽  
Author(s):  
Dongyong Yang ◽  
Fangfang Dai ◽  
Mengqin Yuan ◽  
Yajing Zheng ◽  
Shiyi Liu ◽  
...  

Transforming growth factor-β (TGF-β) is composed of three isoforms, TGF-β1, TGF-β2, and TGF-β3. TGF-β1 is a cytokine with multiple biological functions that has been studied extensively. It plays an important role in regulating the differentiation of immune cells and maintaining immune cell functions and immune homeostasis. Pregnancy is a carefully regulated process. Controlled invasion of trophoblasts, precise coordination of immune cells and cytokines, and crosstalk between trophoblasts and immune cells play vital roles in the establishment and maintenance of normal pregnancy. In this systematic review, we summarize the role of TGF-β1 in regulating fetal-maternal immune tolerance in healthy and pathological pregnancies. During healthy pregnancy, TGF-β1 induces the production of regulatory T cells (Tregs), maintains the immunosuppressive function of Tregs, mediates the balance of M1/M2 macrophages, and regulates the function of NK cells, thus participating in maintaining fetal-maternal immune tolerance. In addition, some studies have shown that TGF-β1 is dysregulated in patients with recurrent spontaneous abortion or preeclampsia. TGF-β1 may play a role in the occurrence and development of these diseases and may be a potential target for the treatment of these diseases.


2021 ◽  
Author(s):  
Preeti Sharma ◽  
Anjali Vijaykumar ◽  
Jayashree Vijaya Raghavan ◽  
Supriya Rajendra Rananaware ◽  
Alakesh Alakesh ◽  
...  

AbstractHumans are exposed to numerous synthetic foreign particulates in the form of environmental pollutants and diagnostic or therapeutic agents. Specialized immune cells (phagocytes) clear these particulates by phagocytosing and attempting to degrade them. The process of recognition and internalization of the particulates may trigger changes in the function of phagocytes. Some of these changes, especially the ability of a particle-loaded phagocyte to take up and neutralize pathogens, remains poorly studied. Herein, we demonstrate that the uptake of non-stimulatory cargo-free particles enhances the phagocytic ability of monocytes, macrophages and neutrophils. The enhancement in phagocytic ability was independent of particle properties, such as size or the base material constituting the particle. Additionally, we show that the increased phagocytosis was not a result of cellular activation or cellular heterogeneity but was driven by changes in cell membrane fluidity and cellular compliance. A consequence of the enhanced phagocytic activity was that particulate-laden immune cells neutralize E. coli faster in culture. Moreover, when administered in mice as a prophylactic, particulates enable faster clearance of E. coli and S. epidermidis. Together, we demonstrate that the process of uptake induces cellular changes that favor additional phagocytic events. This study provides insights into using non-stimulatory cargo-free particles to engineer immune cell functions for applications involving faster clearance of phagocytosable particulates.


2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Juliana Hofstatter Azambuja ◽  
Nils Ludwig ◽  
Saigopalakrishna Yerneni ◽  
Aparna Rao ◽  
Elizandra Braganhol ◽  
...  

Abstract Background Glioblastoma is one of the most immunosuppressive human tumors. Emerging data suggest that glioblastoma-derived exosomes (GBex) reprogram the tumor microenvironment into a tumor-promoting milieu by mechanisms that not yet understood. Methods Exosomes were isolated from supernatants of glioblastoma cell lines by size exclusion chromatography. The GBex endosomal origin, size, protein cargos, and ex vivo effects on immune cell functions were determined. GBex were injected intravenously into mice to evaluate their ability to in vivo modulate normal immune cell subsets. Results GBex carried immunosuppressive proteins, including FasL, TRAIL, CTLA-4, CD39, and CD73, but contained few immunostimulatory proteins. GBex co-incubated with primary human immune cells induced simultaneous activation of multiple molecular pathways. In CD8+ T cells, GBex suppressed TNF-α and INF-γ release and mediated apoptosis. GBex suppressed natural killer (NK) and CD4+ T-cell activation. GBex activated the NF-κB pathway in macrophages and promoted their differentiation into M2 cells. Inhibition of the NF-κB pathway in macrophages reversed the GBex-mediated effects. GBex-driven reprogramming of macrophages involved the release of soluble factors that promoted tumor proliferation in vitro. In mice injected with GBex, the frequency of splenic CD8+ T cells, NK cells, and M1-like macrophages was reduced, while that of naïve and M2-like macrophages increased (P < .05). Conclusions GBex reprogrammed functions of all types of immune cells in vitro and altered their frequency in vivo. By creating and sustaining a highly immunosuppressive environment, GBex play a key role in promoting tumor progression.


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