Dataset Information

The amino acid homoarginine inhibits atherogenesis by modulating T-cell function

ABSTRACT: Rational: Amino acid metabolism is crucial for inflammatory processes during atherogenesis. The endogenous amino acid homoarginine (HA) is a robust biomarker for cardiovascular outcome and mortality with high levels being protective. However, the underlying molecular mechanism remains elusive. Objective: We investigated the effect of HA supplementation on atherosclerotic plaque development with a particular focus on athero-inflammation. Methods and Results: Female apolipoprotein (Apo) E-deficient mice were supplemented with HA (14 mg/L) in drinking water starting two weeks before and continuing throughout a six week-course of Western-type diet (HA-treated). Control mice (Ctrl) received normal drinking water. HA supplementation led to a 2-fold increase in circulating HA concentrations. Plaque- and immunological phenotyping revealed that HA-treated mice exhibited a reduction in atherosclerosis in the aortic root as well as in the brachiocephalic trunk. A substantial decrease in lesion CD3+ T cells suggested a T cell-related effect of HA supplementation. Using mass spectrometry-based proteomics and subsequent pathway analysis together with conventional in vitro techniques such as flow cytometry, various migration and chemotaxis assays as well as super-resolution microscopy, we demonstrate that HA profoundly modulated the spatial organization of the T-cell actin cytoskeleton. Further mechanistic studies revealed an inhibition of T-cell activation and proliferation as well as a striking impairment of the migratory capacities of T cells in response to relevant chemokines by HA, all of which likely contribute to its atheroprotective effects. Conclusion: This study unravels a novel mechanism, by which the amino acid HA reduces atherosclerosis, namely the regulation of T-cell functions crucial for adaptive immunity. We identified that HA modulates the T-cell cytoskeleton and thereby mitigated important T-cell functions during atherogenesis. These findings provide a molecular explanation for the beneficial effects of HA in atherosclerotic cardiovascular disease.

INSTRUMENT(S): Q Exactive HF

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Spleen, T Cell, Lymph Node, Blood

DISEASE(S): Atherosclerosis

SUBMITTER: Ignasi Forne

LAB HEAD: Dorothee Atzler, PhD

PROVIDER: PXD023960 | Pride | 2023-01-30

REPOSITORIES: Pride

ACCESS DATA

Publications

The Amino Acid Homoarginine Inhibits Atherogenesis by Modulating T-Cell Function.

Nitz Katrin K Nitz Katrin K Lacy Michael M Bianchini Mariaelvy M Wichapong Kanin K Kücükgöze Irem Avcilar IA Bonfiglio Cecilia A CA Migheli Roberta R Wu Yuting Y Burger Carina C Li Yuanfang Y Forné Ignasi I Ammar Constantin C Janjic Aleksandar A Mohanta Sarajo S Duchene Johan J Heemskerk Johan W M JWM Megens Remco T A RTA Schwedhelm Edzard E Huveneers Stephan S Lygate Craig A CA Santovito Donato D Zimmer Ralf R Imhof Axel A Weber Christian C Lutgens Esther E Atzler Dorothee D

Circulation research 20220914 8

<h4>Background</h4>Amino acid metabolism is crucial for inflammatory processes during atherogenesis. The endogenous amino acid homoarginine is a robust biomarker for cardiovascular outcome and mortality with high levels being protective. However, the underlying mechanisms remain elusive. We investigated the effect of homoarginine supplementation on atherosclerotic plaque development with a particular focus on inflammation.<h4>Methods</h4>Female ApoE-deficient mice were supplemented with homoargi ...[more]

PMID: 36102188

Similar Datasets

Project description:Regression of atherosclerosis is an important clinical goal, however the pathways that mediate the resolution of atherosclerotic inflammation and reversal of plaques are poorly understood. Regulatory T cells (Tregs) have been shown to be atheroprotective, however numbers of these immunosuppressive cells decrease with disease progression. Using multiple independent mouse models of atherosclerosis regression, we demonstrate that an increase in plaque Tregs is a common signature of regressing plaques. To test if Tregs are required for the resolution of atherosclerotic inflammation and plaque regression during lipid-lowering therapy, we combined CD25 monoclonal antibody (PC61 mAb)-mediated Treg depletion with single-cell RNA-sequencing of immune cells in the plaque and conventional analyses of atherosclerosis. Single cell RNA-sequencing revealed that Tregs from aortic plaques shared some similarity with splenic Tregs, but were distinct from skin and colon Tregs supporting recent findings of tissue-dependent Treg heterogeneity. Furthermore, Tregs from progressing plaques expressed markers of natural Tregs derived from the thymus, whereas Tregs in regressing plaques lacked Nrp1 and Helios expression, suggesting that they are induced in the periphery during lipid lowering. Treatment of atherosclerotic mice with PC61 mAb effectively depleted Tregs in the blood and peripheral tissues, including plaques, and blocked the regression of atherosclerosis induced by apoB anti-sense oligonucleotides. Morphometric analyses revealed that control antibody-treated mice showed a 40% decrease in plaque burden and macrophage content under regression conditions, whereas PC61 mAb-treated mice showed no change in plaque size or inflammatory cell content compared to baseline. Moreover, Treg depletion enhanced inflammatory signaling and blocked tissue reparative functions of macrophages in the regressing plaque, including M2-polarization, efferocytosis and sensing of specialized pro-resolving lipid mediators. Together, these data establish essential roles for Tregs in the resolution of atherosclerotic inflammation and plaque remodeling during regression.

Project description:Atherosclerosis represents an age-related disease, which remains one of the leading cause of deaths in developed countries. It begins with a local deposition of lipid in the innermost part of the artery – intima. Thereafter a number of immune cells are attracted and infiltrate into the artery wall, where, together with endothelia and smooth muscle cells, form an atherosclerotic plaque (Libby, 2008). Thus, atherosclerosis is considered as an inflammatory disease, characterized by intense immunological activity (Libby P, 2012). One of the main risk factor for atherosclerosis is aging. It was demonstrated that there is an accumulation of senescent cells within atherosclerotic plaque (..). Accordingly, vascular smooth muscle cells (VSMCs) derived from the lesion demonstrate a phenotype characteristic for senescent cells: diminished proliferative potential, shorter telomeres, increased number of DNA damage and upregulation of SA-β-gal activity (Gorenne, 2006; Matthes, 2006, Mahomoudi, 2008). Accumulation of senescent VSMCs within the area of plaque development promotes its instability due to lack of proliferation and impaired production of extracellular matrix, both leading to weakening of fibrous cap (Gorenne, 2006). This has been further confirmed by the observation, that elimination of senescent cells in the atherosclerosis-prone low-density lipoprotein receptor-deficient (Ldlr-/-) mice slowed down the disease progression (27789842). One of the most important feature of senescent cells, that has the biggest impact on tissue microenvironment, is their ability to secrete a number of cytokines, chemokines, matrix metalloproteinases and growth factors collectively known as the Senescence Associated Secretory Phenotype (SASP) (20078217, 28165648). Apart from soluble factors, senescent cells secret also an increased number of extracellular vesicles (EVs), research of which has only recently begun (32461143). EVs are small membranous vesicles that can be categorized based on their size and origin, into: exosomes, microvesicles and apoptotic bodies. EVs play crucial role as carriers of proteins, different types of RNA and DNA, lipids and metabolites that, take part in intercellular communication (23420871). They were shown to participate in many physiological but also pathological conditions. Studies performed over the last decade proved that EVs affect atherosclerosis progression at different stages by several distinct mechanisms (as reviewed by Knokhot, 2020, 33261815). The increased concentrations of EVs have been found in plasma of patients suffering from cardiovascular diseases as well as in atherosclerotic plaque itself (Yin, 2015, 26142082; Rautou, 2011, 21852557). However, the role of EVs derived from senescent cells in atherosclerosis, particularly in the context of the plaque development, remains unknown. The functioning of immune cells within atherosclerotic plaque is modulated by local milieu. Thus, senescent cells present in the lesion can influence plaque development by non-cell autonomous mechanism. Indeed, recently it was demonstrated that SASP factors secreted by senescent VSMCs promote recruitment of monocytes, induce expression of adhesion receptors on endothelial cells and activate adjacent normal VSMCs, promoting inflammation in the plaque (Gardner, 2015). However, the role of EVs in this context has not been studied. Thus, we have undertaken research aimed at investigating the role of senescent cell derived EVs on immune cells activity. To this end, we isolated and characterized the EVs secreted by human VSMCs undergoing senescence. We performed unbiased quantitative proteomic analysis of both soluble and insoluble SASP components. Moreover, we analyzed the influence of EVs derived from senescent and non-senescent cells on T lymphocytes and monocytes. Altogether our studies revealed that EVs produced by senescent VSMCs strengthen inflammatory response of the immune cells, what would have a tremendous significance in atherosclerotic plaque development.

Dataset Information

The amino acid homoarginine inhibits atherogenesis by modulating T-cell function

Publications

The Amino Acid Homoarginine Inhibits Atherogenesis by Modulating T-Cell Function.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure