scholarly journals The Role of O-GlcNAcylation in Immune Cell Activation

2021 ◽  
Vol 12 ◽  
Author(s):  
Amy Qiang ◽  
Chad Slawson ◽  
Patrick E. Fields

O-GlcNAcylation is a dynamic post-translational modification where the sugar, O-linked β-N-acetylglucosamine (O-GlcNAc) is added to or removed from various cytoplasmic, nuclear, and mitochondrial proteins. This modification is regulated by only two enzymes: O-GlcNAc transferase (OGT), which adds O-GlcNAc, and O-GlcNAcase (OGA), which removes the sugar from proteins. O-GlcNAcylation is integral to maintaining normal cellular function, especially in processes such as nutrient sensing, metabolism, transcription, and growth and development of the cell. Aberrant O-GlcNAcylation has been associated with a number of pathological conditions, including, neurodegenerative diseases, cancer, diabetes, and obesity. However, the role of O-GlcNAcylation in immune cell growth/proliferation, or other immune responses, is currently incompletely understood. In this review, we highlight the effects of O-GlcNAcylation on certain cells of the immune system, especially those involved in pro-inflammatory responses associated with diabetes and obesity.

2021 ◽  
Vol 116 (1) ◽  
Author(s):  
Marius Keller ◽  
Valbona Mirakaj ◽  
Michael Koeppen ◽  
Peter Rosenberger

AbstractCardiovascular pathologies are often induced by inflammation. The associated changes in the inflammatory response influence vascular endothelial biology; they complicate the extent of ischaemia and reperfusion injury, direct the migration of immune competent cells and activate platelets. The initiation and progression of inflammation is regulated by the classical paradigm through the system of cytokines and chemokines. Therapeutic approaches have previously used this knowledge to control the extent of cardiovascular changes with varying degrees of success. Neuronal guidance proteins (NGPs) have emerged in recent years and have been shown to be significantly involved in the control of tissue inflammation and the mechanisms of immune cell activation. Therefore, proteins of this class might be used in the future as targets to control the extent of inflammation in the cardiovascular system. In this review, we describe the role of NGPs during cardiovascular inflammation and highlight potential therapeutic options that could be explored in the future.


Hypertension ◽  
2020 ◽  
Vol 76 (Suppl_1) ◽  
Author(s):  
David M Patrick ◽  
Nestor de la Visitacion ◽  
Michelle J Ormseth ◽  
Charles Stein ◽  
Sean S Davies ◽  
...  

Essential hypertension and systemic lupus erythematosus (SLE) are devastating conditions that disproportionately affect women. SLE has heterogeneous manifestations and treatment is limited to the use of non-specific global immunosuppression. Importantly, there is an increased prevalence of hypertension in women with SLE compared to healthy controls. Isolevuglandins (IsoLGs) are oxidation products of fatty acids that form as a result of reactive oxygen species. These molecules adduct covalently to lysine residues of proteins. Adducted proteins are then presented as autoantigens to T-cells resulting in immune cell activation. Previous studies have shown an essential role of IsoLGs in immune cell activation and the development of hypertension in animal models. We hypothesize that isoLGs are important for the development of hypertension and systemic immune activation in SLE. We first examined isoLG adduct accumulation within monocytes of human subjects with SLE compared to healthy controls. By flow cytometry, we found marked accumulation of isoLG adducts within CD14 + monocytes (34.2% ± 12.4% vs 3.81% ± 2.1% of CD14 + , N = 10-11, P <0.05). We confirmed this increase in isoLG adducts by mass spectrometry. To determine a causative role of isoLG adducts in immune activation and hypertension in SLE, we employed the B6.SLE123 and NZBWF1 mouse models of SLE. Animals were treated with the isoLG scavenger 2-hydroxybenzylamine (2-HOBA) or vehicle beginning at 7 weeks and were sacrificed at 32 weeks of age. C57BL/6 and NZW were used as controls. Importantly, treatment with 2-HOBA attenuated blood pressure in both mouse models (systolic BP 136.2 ± 5.6 mmHg for B6.SLE123 vs 120.9 ± 4.46 mmHg for B6.SLE123 +2HOBA; 164.7 ± 24.4 mmHg for NZBWF1 vs 136.9 ± 14.9 mmHg for NZBWF1 +2HOBA, N = 6-8, P < 0.05). Moreover, treatment with 2-HOBA reduced albuminuria and renal injury in the B6.SLE123 model (albumin/creatinine ratio 33.8 ± 2.0 x 10 -2 μg/mg for B6.SLE123 vs 5.5 ± 0.9 x 10 -2 μg/mg for B6.SLE123 +2HOBA, N = 7-9, P < 0.05). Finally, immune cell accumulation in primary and secondary lymphoid organs is significantly attenuated by 2-HOBA. These studies suggest a critical role of isoLG adduct accumulation in both systemic immune activation and hypertension in SLE.


2019 ◽  
Vol 30 ◽  
pp. vii25-vii26
Author(s):  
M. Sokac ◽  
L. Dyrskjøt Andersen ◽  
M. Roelsgaard Jakobsen ◽  
N. Birkbak

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Xueyi Zhu ◽  
Jie Cui ◽  
La Yi ◽  
Jingjing Qin ◽  
Wuniqiemu Tulake ◽  
...  

Asthma is associated with innate and adaptive immunity mediated by immune cells. T cell or macrophage dysfunction plays a particularly significant role in asthma pathogenesis. Furthermore, crosstalk between them continuously transmits proinflammatory or anti-inflammatory signals, causing the immune cell activation or repression in the immune response. Consequently, the imbalanced immune microenvironment is the major cause of the exacerbation of asthma. Here, we discuss the role of T cells, macrophages, and their interactions in asthma pathogenesis.


2020 ◽  
Vol 117 (28) ◽  
pp. 16616-16625
Author(s):  
Yunfan Yang ◽  
Xiruo Li ◽  
Harding H. Luan ◽  
Bichen Zhang ◽  
Kaisi Zhang ◽  
...  

Enhanced inflammation is believed to contribute to overnutrition-induced metabolic disturbance. Nutrient flux has also been shown to be essential for immune cell activation. Here, we report an unexpected role of nutrient-sensingO-linked β-N-acetylglucosamine (O-GlcNAc) signaling in suppressing macrophage proinflammatory activation and preventing diet-induced metabolic dysfunction. Overnutrition stimulates an increase inO-GlcNAc signaling in macrophages.O-GlcNAc signaling is down-regulated during macrophage proinflammatory activation. SuppressingO-GlcNAc signaling byO-GlcNAc transferase (OGT) knockout enhances macrophage proinflammatory polarization, promotes adipose tissue inflammation and lipolysis, increases lipid accumulation in peripheral tissues, and exacerbates tissue-specific and whole-body insulin resistance in high-fat-diet-induced obese mice. OGT inhibits macrophage proinflammatory activation by catalyzing ribosomal protein S6 kinase beta-1 (S6K1)O-GlcNAcylation and suppressing S6K1 phosphorylation and mTORC1 signaling. These findings thus identify macrophageO-GlcNAc signaling as a homeostatic mechanism maintaining whole-body metabolism under overnutrition.


2016 ◽  
Vol 311 (4) ◽  
pp. R714-R720 ◽  
Author(s):  
Lia E. Taylor ◽  
Jennifer C. Sullivan

Obesity is a potent predictor of cardiovascular disease and associated risk factors, including hypertension. Systemic inflammation has been suggested by a number of studies to be an important link between excess adiposity and hypertension, yet the majority of the studies have been conducted exclusively in males. This is problematic since women represent ∼53% of hypertensive cases and are more likely than men to be obese. There is a growing body of literature supporting a central role for immune cell activation in numerous experimental models of hypertension, and both the sex of the subject and the sex of the T cell have been shown to impact blood pressure (BP) responses to hypertensive stimuli. Moreover, sex steroid hormones play an important role in energy homeostasis, as well as in the regulation of immune responses; estrogen, in particular, has a well-known impact on both cardiovascular and metabolic disorders. Therefore, the purpose of this review is to examine whether sex or sex hormones regulate the role of the immune system in the development of hypertension and related vascular dysfunction in response to metabolic changes and stimuli, including a high-fat diet.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jisun So ◽  
Albert K. Tai ◽  
Alice H. Lichtenstein ◽  
Dayong Wu ◽  
Stefania Lamon-Fava

AbstractSexual dimorphism in the immune system is evidenced by a higher prevalence of autoimmune diseases in women and higher susceptibility to infectious diseases in men. However, the molecular basis of these sex-based differences is not fully understood. We have characterized the transcriptome profiles of peripheral blood monocytes from males and postmenopausal females with chronic low-grade inflammation. We identified 41 sexually differentially expressed genes [adjusted p value (FDR) < 0.1], including genes involved in immune cell activation (e.g., CEACAM1, FCGR2B, and SLAMF7) and antigen presentation (e.g., AIM2, CD1E, and UBA1) with a higher expression in females than males. Moreover, signaling pathways of immune or inflammatory responses, including interferon (IFN) signaling [z-score = 2.45, -log(p) = 3.88], were found to be more upregulated in female versus male monocytes, based on a set of genes exhibiting sex-biased expression (p < 0.03). The contribution of IFN signaling to the sexual transcriptional differences was further confirmed by direct comparisons of the monocyte sex-biased genes with IFN signature genes (ISGs) that were previously curated in mouse macrophages. ISGs showed a greater overlap with female-biased genes than male-biased genes and a higher overall expression in female than male monocytes, particularly for the genes of antiviral and inflammatory responses to IFN. Given the role of IFN in immune defense and autoimmunity, our results suggest that sexual dimorphism in immune functions may be associated with more priming of innate immune pathways in female than male monocytes. These findings highlight the role of sex on the human immune transcriptome.


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