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

TY - JOUR

T1 - The Amino Acid Homoarginine Inhibits Atherogenesis by Modulating T-Cell Function

AU - Nitz, Katrin

AU - Lacy, Michael

AU - Bianchini, Mariaelvy

AU - Wichapong, Kanin

AU - Kücükgöze, Irem Avcilar

AU - Bonfiglio, Cecilia A

AU - Migheli, Roberta

AU - Wu, Yuting

AU - Burger, Carina

AU - Li, Yuanfang

AU - Forné, Ignasi

AU - Ammar, Constantin

AU - Janjic, Aleksandar

AU - Mohanta, Sarajo

AU - Duchene, Johan

AU - Heemskerk, Johan W M

AU - Megens, Remco T A

AU - Schwedhelm, Edzard

AU - Huveneers, Stephan

AU - Lygate, Craig A

AU - Santovito, Donato

AU - Zimmer, Ralf

AU - Imhof, Axel

AU - Weber, Christian

AU - Lutgens, Esther

AU - Atzler, Dorothee

PY - 2022/9/30

Y1 - 2022/9/30

N2 - BACKGROUND: 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.METHODS: Female ApoE-deficient mice were supplemented with homoarginine (14 mg/L) in drinking water starting 2 weeks before and continuing throughout a 6-week period of Western-type diet feeding. Control mice received normal drinking water. Immunohistochemistry and flow cytometry were used for plaque- and immunological phenotyping. T cells were characterized using mass spectrometry-based proteomics, by functional in vitro approaches, for example, proliferation and migration/chemotaxis assays as well as by super-resolution microscopy.RESULTS: Homoarginine supplementation led to a 2-fold increase in circulating homoarginine concentrations. Homoarginine-treated mice exhibited reduced atherosclerosis in the aortic root and brachiocephalic trunk. A substantial decrease in CD3+ T cells in the atherosclerotic lesions suggested a T-cell-related effect of homoarginine supplementation, which was mainly attributed to CD4+ T cells. Macrophages, dendritic cells, and B cells were not affected. CD4+ T-cell proteomics and subsequent pathway analysis together with in vitro studies demonstrated that homoarginine profoundly modulated the spatial organization of the T-cell actin cytoskeleton and increased filopodia formation via inhibition of Myh9 (myosin heavy chain 9). Further mechanistic studies revealed an inhibition of T-cell proliferation as well as a striking impairment of the migratory capacities of T cells in response to relevant chemokines by homoarginine, all of which likely contribute to its atheroprotective effects.CONCLUSIONS: Our study unravels a novel mechanism by which the amino acid homoarginine reduces atherosclerosis, establishing that homoarginine modulates the T-cell cytoskeleton and thereby mitigates T-cell functions important during atherogenesis. These findings provide a molecular explanation for the beneficial effects of homoarginine in atherosclerotic cardiovascular disease.

AB - BACKGROUND: 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.METHODS: Female ApoE-deficient mice were supplemented with homoarginine (14 mg/L) in drinking water starting 2 weeks before and continuing throughout a 6-week period of Western-type diet feeding. Control mice received normal drinking water. Immunohistochemistry and flow cytometry were used for plaque- and immunological phenotyping. T cells were characterized using mass spectrometry-based proteomics, by functional in vitro approaches, for example, proliferation and migration/chemotaxis assays as well as by super-resolution microscopy.RESULTS: Homoarginine supplementation led to a 2-fold increase in circulating homoarginine concentrations. Homoarginine-treated mice exhibited reduced atherosclerosis in the aortic root and brachiocephalic trunk. A substantial decrease in CD3+ T cells in the atherosclerotic lesions suggested a T-cell-related effect of homoarginine supplementation, which was mainly attributed to CD4+ T cells. Macrophages, dendritic cells, and B cells were not affected. CD4+ T-cell proteomics and subsequent pathway analysis together with in vitro studies demonstrated that homoarginine profoundly modulated the spatial organization of the T-cell actin cytoskeleton and increased filopodia formation via inhibition of Myh9 (myosin heavy chain 9). Further mechanistic studies revealed an inhibition of T-cell proliferation as well as a striking impairment of the migratory capacities of T cells in response to relevant chemokines by homoarginine, all of which likely contribute to its atheroprotective effects.CONCLUSIONS: Our study unravels a novel mechanism by which the amino acid homoarginine reduces atherosclerosis, establishing that homoarginine modulates the T-cell cytoskeleton and thereby mitigates T-cell functions important during atherogenesis. These findings provide a molecular explanation for the beneficial effects of homoarginine in atherosclerotic cardiovascular disease.

KW - Amino Acids

KW - Animals

KW - Apolipoproteins E

KW - Atherosclerosis/drug therapy

KW - Drinking Water

KW - Female

KW - Homoarginine/pharmacology

KW - Mice

KW - Myosin Heavy Chains

KW - Plaque, Atherosclerotic

KW - T-Lymphocytes/metabolism

U2 - 10.1161/CIRCRESAHA.122.321094

DO - 10.1161/CIRCRESAHA.122.321094

M3 - SCORING: Journal article

C2 - 36102188

VL - 131

SP - 701

EP - 712

JO - CIRC RES

JF - CIRC RES

SN - 0009-7330

IS - 8

ER -