Liraglutide Attenuates Myocardial Fibrosis via Inhibition of AT1R-Mediated ROS Production in Hypertensive Mice

Author(s):  
Peng Chen ◽  
Fen Yang ◽  
Wenya Wang ◽  
Xiao Li ◽  
Dongling Liu ◽  
...  

Background/Aims: Glucagon-like peptide-1 receptor agonist liraglutide has been reported to exert cardioprotective effects, but its effect on cardiac fibrosis remains controversial. The aim of this study was to investigate the effects of liraglutide on cardiac fibrosis and potential mechanisms. Methods: C57BL/6 mice (3-month old) were randomly divided into control, hypertension, and hypertension + liraglutide groups. The hypertensive state was created by infusion of Ang II (100 ng/kg·min) for 4 weeks through subcutaneously implanted osmotic pumps. The control mice were infused with saline. Mice were also given vehicle or liraglutide (400 μg/kg·day). Blood pressure (BP), blood sugar, myocardial fibrosis, AT1R expression, and reactive oxygen species (ROS) levels were measured. To further elucidate the mechanisms of fibrosis, mouse cardiac fibroblasts were isolated and treated with liraglutide (300 nM/L) or losartan (10 μM) for 3 hours, followed by Ang II (10−7 M) for additional 12 hours. Reactive oxygen species production and expressions of collagen-1 and -3 were measured. Results: Liraglutide reduced BP and blood sugar but did not affect the body weight of the hypertensive mice. Liraglutide also inhibited collagen accumulation, AT1R expression, and ROS generation in the hearts of the hypertensive mice. In in vitro studies, pretreatment with liraglutide and losartan (as control) markedly inhibited Ang II-induced ROS production and collagen expression in the cultured cardiac fibroblasts. Conclusion: Liraglutide reduces myocardial fibrosis in the hypertensive mice, which appears to be dependent on at least in part inhibition of ROS production.

2015 ◽  
Vol 36 (3) ◽  
pp. 917-929 ◽  
Author(s):  
Dan Zheng ◽  
Shiyun Dong ◽  
Ting Li ◽  
Fan Yang ◽  
Xiangjing Yu ◽  
...  

Background: Oxidative stress inducing hyperglycemia and high glucose play an important role in the development of cardiac fibrosis associated with diabetic cardiomyopathy. The endogenous gasotransmitter hydrogen sulfide (H2S) can act in a cytoprotective manner. However, whether H2S could inhibit the fibrotic process is unclear. The purpose of our study was to examine the role of H2S in the development and underlying mechanisms behind diabetic cardiomyopathy. Methods: Diabetic cardiomyopathy was induced in rats by injection of streptozotocin (STZ). Cardiac fibrosis and proliferation of rat neonatal cardiac fibroblasts were induced by hyperglycemia and high glucose. We tested the effects of GYY4137 (a slow-releasing H2S donor), NaHS (an exogenous H2S donor) and NADPH oxidase 4 (NOX4) siRNA on reactive oxygen species (ROS) production, MMP-2,9, cystathionine-γ-lyase (CSE), NOX4, and extracellular signal-regulated kinase 1/2 (ERK1/2) to reveal the effects of H2S on the cardiac fibrosis of diabetic cardiomyopathy. Result: In vivo, NaHS treatment inhibited hyperglycemia-induced expression of type I and III collagen, MMP-2 and MMP-9 in diabetic hearts. Rat neonatal cardiac fibroblast migration and cell survival were inhibited by administration of GYY4137. NOX4 expression was increased by hyperglycemia and high glucose, but was reduced in cardiac fibroblasts treated by NaHS and GYY4137. ROS production, ERK1/2 phosphorylation and MMP-2 and 9 expression were decreased in rat neonatal cardiac fibroblasts treated with GYY4137 and NOX4 siRNA. Conclusion: The present study shows that enhanced NOX4 expression results in cardiac fibrosis through ROS-ERK1/2-MAPkinase-dependent mechanisms in diabetic cardiomyopathy. NOX4 could be an important target for H2S to regulate redox homeostasis in cardiac fibrosis of diabetic cardiomyopathy.


2017 ◽  
Vol 95 (5) ◽  
pp. 474-480 ◽  
Author(s):  
Ting-Bo Li ◽  
Jie-Jie Zhang ◽  
Bin Liu ◽  
Xiu-Ju Luo ◽  
Qi-Lin Ma ◽  
...  

NADPH oxidase (NOX) is a major source of reactive oxygen species (ROS) in the body and it plays a key role in mediation of oxidative injury in the cardiovascular system. The purposes of this study are to evaluate the status of NOX in endothelial progenitor cells (EPCs) of hyperlipidemic rats and to determine whether NOX-derived ROS promotes the dysfunction of EPCs. The rats were fed on a high-fat diet for 8 weeks to establish a hyperlipidemic rat model, which showed the increased plasma lipids and the impaired functions of circulating EPCs (including the reduced abilities in migration and adhesion) accompanied by an increase in NOX activity and ROS production. Next, EPCs were isolated from normal rats and they were treated with oxidized low-density lipoprotein (ox-LDL) (100 μg/mL) for 24 h to induce a dysfunctional model in vitro. In agreement with our findings in vivo, ox-LDL treatment increased the dysfunctions of EPCs concomitant with an increase in NOX activity and ROS production; these phenomena were reversed by the NOX inhibitor. Based on these observations, we conclude that NOX-derived ROS involved in the dysfunctions of circulating EPCs in hyperlipidemic rats and inhibition of NOX might provide a novel strategy to improve EPC functions in hyperlipidemia.


2008 ◽  
Vol 295 (3) ◽  
pp. H1025-H1032 ◽  
Author(s):  
Baojian Xue ◽  
Yuanzi Zhao ◽  
Alan Kim Johnson ◽  
Meredith Hay

It has been shown that reactive oxygen species (ROS) contribute to the central effect of ANG II on blood pressure (BP). Recent studies have implicated an antihypertensive action of estrogen in ANG II-infused female mice. The present study used in vivo telemetry recording and in vitro living mouse brain slices to test the hypothesis that the central activation of estrogen receptors in male mice inhibits ANG II-induced hypertension via the modulation of the central ROS production. In male wild-type mice, the systemic infusion of ANG II induced a significant increase in BP (Δ30.1 ± 2.5 mmHg). Either central infusion of Tempol or 17β-estradiol (E2) attenuated the pressor effect of ANG II (Δ10.9 ± 2.3 and Δ4.5 ± 1.4 mmHg), and the protective effect of E2 was prevented by the coadministration of an estrogen receptor, antagonist ICI-182780 (Δ23.6 ± 3.1 mmHg). Moreover, the ganglionic blockade on day 7 after the start of ANG II infusions resulted in a smaller reduction of BP in central Tempol- and in central E2-treated males, suggesting that estrogen inhibits the central ANG II-induced increases in sympathetic outflow. In subfornical organ slices, the application of ANG II resulted in a 21.5 ± 2.5% increase in ROS production. The coadministration of irbesartan, an ANG II type 1 receptor antagonist, or the preincubation of brain slices with Tempol blocked ANG II-induced increases in ROS production (−1.8 ± 1.6% and −1.0 ± 1.8%). The ROS response to ANG II was also blocked by E2 (−3.2 ± 2.4%). The results suggest that the central actions of E2 are involved in the protection from ANG II-induced hypertension and that estrogen modulation of the ANG II-induced effects may involve interactions with ROS production.


2012 ◽  
Vol 302 (4) ◽  
pp. H901-H909 ◽  
Author(s):  
Rukhsana Gul ◽  
Asif Iqbal Shawl ◽  
Suhn-Hee Kim ◽  
Uh-Hyun Kim

Reactive oxygen species (ROS) and Ca2+ signals are closely associated with the pathogenesis of cardiac hypertrophy. However, the cause and effect of the two signals in cardiac hypertrophy remain to be clarified. We extend our recent report by investigating a potential interaction between ROS and Ca2+ signals utilizing in vitro and in vivo angiotensin II (ANG II)-induced cardiac hypertrophy models. ANG II-induced initial Ca2+ transients mediated by inositol trisphosphate (IP3) triggered initial ROS production in adult rat cardiomyocytes. The ROS generated by activation of the NAD(P)H oxidase complex via Rac1 in concert with Ca2+ activates ADP-ribosyl cyclase to generate cyclic ADP-ribose (cADPR). This messenger-mediated Ca2+ signal further augments ROS production, since 2,2′-dihydroxyazobenzene, an ADP-ribosyl cyclase inhibitor, or 8-Br-cADPR, an antagonistic analog of cADPR, abolished further ROS production. Data from short hairpin RNA (shRNA)-mediated knockdown of Akt1 and p47phox demonstrated that Akt1 is the upstream key molecule responsible for the initiation of Ca2+ signal that activates p47phox to generate ROS in cardiomyocytes. Nuclear translocation of nuclear factor of activated T-cell in cardiomyocytes was significantly suppressed by treatment with NAD(P)H oxidase inhibitors as well as by shRNA against Akt1 and p47phox. Our results suggest that in cardiomyocytes Ca2+ and ROS messengers generated by ANG II amplify the initial signals in a cooperative manner, thereby leading to cardiac hypertrophy.


Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1586
Author(s):  
Svetlana Veselova ◽  
Tatyana Nuzhnaya ◽  
Guzel Burkhanova ◽  
Sergey Rumyantsev ◽  
Igor Maksimov

Reactive oxygen species (ROS) play a central role in plant immune responses. The most important virulence factors of the Stagonospora nodorum Berk. are multiple fungal necrotrophic effectors (NEs) (SnTox) that affect the redox-status and cause necrosis and/or chlorosis in wheat lines possessing dominant susceptibility genes (Snn). However, the effect of NEs on ROS generation at the early stages of infection has not been studied. We studied the early stage of infection of various wheat genotypes with S nodorum isolates -Sn4VD, SnB, and Sn9MN, carrying a different set of NE genes. Our results indicate that all three NEs of SnToxA, SnTox1, SnTox3 significantly contributed to cause disease, and the virulence of the isolates depended on their differential expression in plants (Triticum aestivum L.). The Tsn1–SnToxA, Snn1–SnTox1and Snn3–SnTox3 interactions played an important role in inhibition ROS production at the initial stage of infection. The Snn3–SnTox3 inhibited ROS production in wheat by affecting NADPH-oxidases, peroxidases, superoxide dismutase and catalase. The Tsn1–SnToxA inhibited ROS production in wheat by affecting peroxidases and catalase. The Snn1–SnTox1 inhibited the production of ROS in wheat by mainly affecting a peroxidase. Collectively, these results show that the inverse gene-for gene interactions between effector of pathogen and product of host sensitivity gene suppress the host’s own PAMP-triggered immunity pathway, resulting in NE-triggered susceptibility (NETS). These results are fundamentally changing our understanding of the development of this economical important wheat disease.


2021 ◽  
Author(s):  
Biz R. Turnell ◽  
Luisa Kumpitsch ◽  
Klaus Reinhardt

AbstractSperm aging is accelerated by the buildup of reactive oxygen species (ROS), which cause oxidative damage to various cellular components. Aging can be slowed by limiting the production of mitochondrial ROS and by increasing the production of antioxidants, both of which can be generated in the sperm cell itself or in the surrounding somatic tissues of the male and female reproductive tracts. However, few studies have compared the separate contributions of ROS production and ROS scavenging to sperm aging, or to cellular aging in general. We measured reproductive fitness in two lines of Drosophila melanogaster genetically engineered to (1) produce fewer ROS via expression of alternative oxidase (AOX), an alternative respiratory pathway; or (2) scavenge fewer ROS due to a loss-of-function mutation in the antioxidant gene dj-1β. Wild-type females mated to AOX males had increased fecundity and longer fertility durations, consistent with slower aging in AOX sperm. Contrary to expectations, fitness was not reduced in wild-type females mated to dj-1β males. Fecundity and fertility duration were increased in AOX and decreased in dj-1β females, indicating that female ROS levels may affect aging rates in stored sperm and/or eggs. Finally, we found evidence that accelerated aging in dj-1β sperm may have selected for more frequent mating. Our results help to clarify the relative roles of ROS production and ROS scavenging in the male and female reproductive systems.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
V. Jaenen ◽  
S. Fraguas ◽  
K. Bijnens ◽  
M. Heleven ◽  
T. Artois ◽  
...  

AbstractDespite extensive research on molecular pathways controlling the process of regeneration in model organisms, little is known about the actual initiation signals necessary to induce regeneration. Recently, the activation of ERK signaling has been shown to be required to initiate regeneration in planarians. However, how ERK signaling is activated remains unknown. Reactive Oxygen Species (ROS) are well-known early signals necessary for regeneration in several models, including planarians. Still, the probable interplay between ROS and MAPK/ERK has not yet been described. Here, by interfering with major mediators (ROS, EGFR and MAPK/ERK), we were able to identify wound-induced ROS, and specifically H2O2, as upstream cues in the activation of regeneration. Our data demonstrate new relationships between regeneration-related ROS production and MAPK/ERK activation at the earliest regeneration stages, as well as the involvement of the EGFR-signaling pathway. Our results suggest that (1) ROS and/or H2O2 have the potential to rescue regeneration after MEK-inhibition, either by H2O2-treatment or light therapy, (2) ROS and/or H2O2 are required for the activation of MAPK/ERK signaling pathway, (3) the EGFR pathway can mediate ROS production and the activation of MAPK/ERK during planarian regeneration.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Biz R. Turnell ◽  
Luisa Kumpitsch ◽  
Anne-Cécile Ribou ◽  
Klaus Reinhardt

Abstract Objective Sperm ageing has major evolutionary implications but has received comparatively little attention. Ageing in sperm and other cells is driven largely by oxidative damage from reactive oxygen species (ROS) generated by the mitochondria. Rates of organismal ageing differ across species and are theorized to be linked to somatic ROS levels. However, it is unknown whether sperm ageing rates are correlated with organismal ageing rates. Here, we investigate this question by comparing sperm ROS production in four lines of Drosophila melanogaster that have previously been shown to differ in somatic mitochondrial ROS production, including two commonly used wild-type lines and two lines with genetic modifications standardly used in ageing research. Results Somatic ROS production was previously shown to be lower in wild-type Oregon-R than in wild-type Dahomey flies; decreased by the expression of alternative oxidase (AOX), a protein that shortens the electron transport chain; and increased by a loss-of-function mutation in dj-1β, a gene involved in ROS scavenging. Contrary to predictions, we found no differences among these four lines in the rate of sperm ROS production. We discuss the implications of our results, the limitations of our study, and possible directions for future research.


2021 ◽  
Author(s):  
Małgorzata Olszowy-Tomczyk

AbstractOxidative stress, associated with an imbalance between the oxidants (reactive oxygen species) and the antioxidants in the body, contributes to the development of many diseases. The body’s fight against reactive oxygen species is supported by antioxidants. Nowadays, there are too many analytical methods, but there is no one universal technique for assessing antioxidant properties. Moreover, the applied different ways of expressing the results lead to their incompatibility and unreasonable interpretation. The paper is a literature review concerning the most frequent ways of antioxidant activities expression and for an easy and universal method of the obtained results discussion. This paper is an attempt to point out their disadvantages and advantages. The manuscript can support the searching interpretation of the obtained results which will be a good tool for the development of a number of fields, especially medicine what can help in the future detection and treatment of many serious diseases. Graphic abstract


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