scholarly journals Altered Ca2+ Homeostasis in Immune Cells during Aging: Role of Ion Channels

2020 ◽  
Vol 22 (1) ◽  
pp. 110
Author(s):  
Dorina Zöphel ◽  
Chantal Hof ◽  
Annette Lis

Aging is an unstoppable process and begins shortly after birth. Each cell of the organism is affected by the irreversible process, not only with equal density but also at varying ages and with different speed. Therefore, aging can also be understood as an adaptation to a continually changing cellular environment. One of these very prominent changes in age affects Ca2+ signaling. Especially immune cells highly rely on Ca2+-dependent processes and a strictly regulated Ca2+ homeostasis. The intricate patterns of impaired immune cell function may represent a deficit or compensatory mechanisms. Besides, altered immune function through Ca2+ signaling can profoundly affect the development of age-related disease. This review attempts to summarize changes in Ca2+ signaling due to channels and receptors in T cells and beyond in the context of aging.

2021 ◽  
Vol 15 ◽  
Author(s):  
Jenny Lutshumba ◽  
Barbara S. Nikolajczyk ◽  
Adam D. Bachstetter

Neuroinflammation and the tissue-resident innate immune cells, the microglia, respond and contribute to neurodegenerative pathology. Although microglia have been the focus of work linking neuroinflammation and associated dementias like Alzheimer’s Disease, the inflammatory milieu of brain is a conglomerate of cross-talk amongst microglia, systemic immune cells and soluble mediators like cytokines. Age-related changes in the inflammatory profile at the levels of both the brain and periphery are largely orchestrated by immune system cells. Strong evidence indicates that both innate and adaptive immune cells, the latter including T cells and B cells, contribute to chronic neuroinflammation and thus dementia. Neurodegenerative hallmarks coupled with more traditional immune system stimuli like infection or injury likely combine to trigger and maintain persistent microglial and thus brain inflammation. This review summarizes age-related changes in immune cell function, with special emphasis on lymphocytes as a source of inflammation, and discusses how such changes may potentiate both systemic and central nervous system inflammation to culminate in dementia. We recap the understudied area of AD-associated changes in systemic lymphocytes in greater detail to provide a unifying perspective of inflammation-fueled dementia, with an eye toward evidence of two-way communication between the brain parenchyma and blood immune cells. We focused our review on human subjects studies, adding key data from animal models as relevant.


Cancers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1280 ◽  
Author(s):  
Rébé ◽  
Ghiringhelli

Immune cells in the tumor microenvironment regulate cancer growth. Thus cancer progression is dependent on the activation or repression of transcription programs involved in the proliferation/activation of lymphoid and myeloid cells. One of the main transcription factors involved in many of these pathways is the signal transducer and activator of transcription 3 (STAT3). In this review we will focus on the role of STAT3 and its regulation, e.g. by phosphorylation or acetylation in immune cells and how it might impact immune cell function and tumor progression. Moreover, we will review the ability of STAT3 to regulate checkpoint inhibitors.


2020 ◽  
Vol 8 (2) ◽  
pp. e000417 ◽  
Author(s):  
Alexandra Borodovsky ◽  
Christine M Barbon ◽  
Yanjun Wang ◽  
Minwei Ye ◽  
Laura Prickett ◽  
...  

Accumulation of extracellular adenosine within the microenvironment is a strategy exploited by tumors to escape detection by the immune system. Adenosine signaling through the adenosine 2A receptor (A2AR) on immune cells elicits a range of immunosuppressive effects which promote tumor growth and limit the efficacy of immune checkpoint inhibitors. Preclinical data with A2AR inhibitors have demonstrated tumor regressions in mouse models by rescuing T cell function; however, the mechanism and role on other immune cells has not been fully elucidated.MethodsWe report here the development of a small molecule A2AR inhibitor including characterization of binding and inhibition of A2AR function with varying amounts of a stable version of adenosine. Functional activity was tested in both mouse and human T cells and dendritic cells (DCs) in in vitro assays to understand the intrinsic role on each cell type. The role of adenosine and A2AR inhibition was tested in DC differentiation assays as well as co-culture assays to access the cross-priming function of DCs. Syngeneic models were used to assess tumor growth alone and in combination with alphaprogrammed death-ligand 1 (αPD-L1). Immunophenotyping by flow cytometry was performed to examine global immune cell changes upon A2AR inhibition.ResultsWe provide the first report of AZD4635, a novel small molecule A2AR antagonist which inhibits downstream signaling and increases T cell function as well as a novel mechanism of enhancing antigen presentation by CD103+ DCs. The role of antigen presentation by DCs, particularly CD103+ DCs, is critical to drive antitumor immunity providing rational to combine a priming agent AZD4635 with check point blockade. We find adenosine impairs the maturation and antigen presentation function of CD103+ DCs. We show in multiple syngeneic mouse tumor models that treatment of AZD4635 alone and in combination with αPD-L1 led to decreased tumor volume correlating with enhanced CD103+ function and T cell response. We extend these studies into human DCs to show that adenosine promotes a tolerogenic phenotype that can be reversed with AZD4635 restoring antigen-specific T cell activation. Our results support the novel role of adenosine signaling as an intrinsic negative regulator of CD103+ DCs maturation and priming. We show that potent inhibition of A2AR with AZD4635 reduces tumor burden and enhances antitumor immunity. This unique mechanism of action in CD103+ DCs may contribute to clinical responses as AZD4635 is being evaluated in clinical trials with IMFINZI (durvalumab, αPD-L1) in patients with solid malignancies.ConclusionWe provide evidence implicating suppression of adaptive and innate immunity by adenosine as a mechanism for immune evasion by tumors. Inhibition of adenosine signaling through selective small molecule inhibition of A2AR using AZD4635 restores T cell function via an internal mechanism as well as tumor antigen cross-presentation by CD103+ DCs resulting in antitumor immunity.


2019 ◽  
Vol 47 (6) ◽  
pp. 1581-1595 ◽  
Author(s):  
Rebecca L. Wallings ◽  
Malú G. Tansey

Mutations in the leucine-rich-repeat kinase 2 (LRRK2) gene are associated with familial and sporadic cases of Parkinson's disease but are also found in immune-related disorders such as inflammatory bowel disease, tuberculosis and leprosy. LRRK2 is highly expressed in immune cells and has been functionally linked to pathways pertinent to immune cell function, such as cytokine release, autophagy and phagocytosis. Here, we examine the current understanding of the role of LRRK2 kinase activity in pathway regulation in immune cells, drawing upon data from multiple diseases associated with LRRK2 to highlight the pleiotropic effects of LRRK2 in different cell types. We discuss the role of the bona fide LRRK2 substrate, Rab GTPases, in LRRK2 pathway regulation as well as downstream events in the autophagy and inflammatory pathways.


2015 ◽  
Vol 43 (4) ◽  
pp. 752-757 ◽  
Author(s):  
Kirsty E. Waddington ◽  
Elizabeth C. Jury ◽  
Inés Pineda-Torra

The liver X receptors (LXRs), LXRα and LXRβ, are transcription factors with well-established roles in the regulation of lipid metabolism and cholesterol homeostasis. In addition, LXRs influence innate and adaptive immunity, including responses to inflammatory stimuli, proliferation and differentiation, migration, apoptosis and survival. However, the majority of work describing the role of LXRs in immune cells has been carried out in mouse models, and there are a number of known species-specific differences concerning LXR function. Here we review what is known about the role of LXRs in human immune cells, demonstrating the importance of these receptors in the integration of lipid metabolism and immune function, but also highlighting the need for a better understanding of the species, isoform, and cell-type specific effects of LXR activation.


Author(s):  
Mohammad Javad Fattahi ◽  
Mohammad Reza Haghshenas ◽  
Abbas Ghaderi

Abstract: The initiation and progression of bladder cancer (BC), is dependent on its tumor microenvironment (TME). On the other hand, cancer cells shape and train TME to support their development, respond to treatment and migration in an organism. Immune cells exert key roles in the BC microenvironment and have complex interactions with BC cells. These complicated interplays result in metabolic competition in the TME leading to nutrient deprivation, acidosis, hypoxia and metabolite accumulation, which impair immune cell function. Recent studies have demonstrated that immune cells functions are closely correlated with their metabolism. Immunometabolism describes the functional metabolic alterations that take place within immune cells and the role of these cells in directing metabolism and immune response in tissues or diseases such as cancer. Some molecules and their metabolites in the TME including glucose, fatty acids and amino acids can regulate the phenotype, function and metabolism of immune cells. Hence, here we describe some recent advances in immunometabolism and relate them to BC progression. A profound understanding of the metabolic reprogramming of BC cells and immune cells in the TME will offer novel opportunities for targeted therapies in future.


Author(s):  
Bruce Kirkham

Psoriatic arthritis immunopathology has become the subject of intense study. These findings show differences to other forms of inflammatory arthritis in key pathways. Increased knowledge of innate immunity and the important role of IL-17/23 biology in both psoriasis and psoriatic arthritis, have led to new theories of immunopathogenesis in both conditions. Direct environmental stimuli could trigger innate immune cells resident in skin, which may then initiate a chronic adaptive immune response. The joint has fewer resident innate immune cells, but new studies show cells producing IL-17 may play key roles in immunopathology. The new information summarized here will provide important hypotheses for investigation of pathogenic pathways. Differences in non-immune cell function may also be critical mediators of response, for example, production of IL-12 or IL-23 by dendritic cells. Keratinocytes in skin and fibroblasts in joints may be critical in mediating cytokine production and effector function.


Author(s):  
Shree Padma Metur ◽  
Daniel J. Klionsky

AbstractThe function of lymphocytes is dependent on their plasticity, particularly their adaptation to energy availability and environmental stress, and their protein synthesis machinery. Lymphocytes are constantly under metabolic stress, and macroautophagy/autophagy is the primary metabolic pathway that helps cells overcome stressors. The intrinsic role of autophagy in regulating the metabolism of adaptive immune cells has recently gained increasing attention. In this review, we summarize and discuss the versatile roles of autophagy in regulating cellular metabolism and the implications of autophagy for immune cell function and fate, especially for T and B lymphocytes.


1995 ◽  
Vol 209 (4) ◽  
pp. 369-375 ◽  
Author(s):  
M. Roy ◽  
L. Kiremidjian-Schumacher ◽  
H. I. Wishe ◽  
M. W. Cohen ◽  
G. Stotzky

Author(s):  
Leena P. Bharath ◽  
Barbara S. Nikolajczyk

The biguanide metformin is the most commonly used antidiabetic drug. Recent studies show that metformin not only improves chronic inflammation by improving metabolic parameters but also has a direct anti-inflammatory effect. In light of these findings, it is essential to identify the inflammatory pathways targeted by metformin to develop a comprehensive understanding of the mechanisms of action of this drug. Commonly accepted mechanisms of metformin action include AMPK activation and inhibition of mTOR pathways, which are evaluated in multiple diseases. Additionally, metformin's action on mitochondrial function and cellular homeostasis processes such as autophagy, is of particular interest because of the importance of these mechanisms in maintaining cellular health. Both dysregulated mitochondria and failure of the autophagy pathways, the latter of which impair clearance of dysfunctional, damaged, or excess organelles, affect cellular health drastically and can trigger the onset of metabolic and age-related diseases. Immune cells are the fundamental cell types that govern the health of an organism. Thus, dysregulation of autophagy or mitochondrial function in immune cells has a remarkable effect on susceptibility to infections, response to vaccination, tumor onset, and the development of inflammatory and autoimmune conditions. Here we summarize the latest research on metformin's regulation of immune cell mitochondrial function and autophagy as evidence that new clinical trials on metformin with primary outcomes related to the immune system should be considered to treat immune-mediated diseases over the near term.


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