scholarly journals Age-related changes to vascular protease-activated receptor 2 in metabolic syndrome: a relationship between oxidative stress, receptor expression, and endothelium-dependent vasodilation

2017 ◽  
Vol 95 (4) ◽  
pp. 356-364 ◽  
Author(s):  
Kana Maruyama ◽  
Satomi Kagota ◽  
John J. McGuire ◽  
Hirokazu Wakuda ◽  
Noriko Yoshikawa ◽  
...  

Protease-activated receptor 2 (PAR2) is expressed in vascular endothelium. Nitric oxide (NO) – cyclic GMP-mediated vasodilation in response to 2-furoyl-LIGRLO-amide (2fLIGRLO), a PAR2-activating peptide, is impaired in aortas from aged SHRSP.Z-Leprfa/IzmDmcr (SHRSP.ZF) rats with metabolic syndrome. Here we investigated mechanisms linking PAR2’s vascular effects to phenotypic characteristics of male SHRSP.ZF rats at 10, 20, and 30 weeks of age. We found vasodilation responses to either 2fLIGRLO or enzyme-mediated PAR2 activation by trypsin were sustained until 20 weeks and lessened at 30 weeks. PAR2 protein and mRNA levels were lower in aortas at 30 weeks than at 10 and 20 weeks. PAR2-mediated responses positively correlated with PAR2 protein and mRNA levels. Decreased cGMP accumulation in the presence of 2fLIGRLO paralleled the decreased relaxations elicited by nitroprusside and the cGMP analog 8-pCPT-cGMP, and the less soluble guanylyl cyclase protein at 30 weeks. 2fLIGRLO-induced relaxation was negatively correlated with serum thiobarbituric acid reactive substances, an index of oxidative stress, which increased with age. Forward stepwise data regression supported a model of age-related decreases in PAR2 function resulting from decreased PAR2 mRNA and increased oxidative stress. We conclude that decreased responsiveness of aortic smooth muscle to NO and downregulation of receptor expression impair PAR2 functions at later stages of metabolic syndrome in SHRSP.ZF rats.

Biology ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 253
Author(s):  
Graciela Gavia-García ◽  
Juana Rosado-Pérez ◽  
Taide Laurita Arista-Ugalde ◽  
Itzen Aguiñiga-Sánchez ◽  
Edelmiro Santiago-Osorio ◽  
...  

A great amount of scientific evidence supports that Oxidative Stress (OxS) can contribute to telomeric attrition and also plays an important role in the development of certain age-related diseases, among them the metabolic syndrome (MetS), which is characterised by clinical and biochemical alterations such as obesity, dyslipidaemia, arterial hypertension, hyperglycaemia, and insulin resistance, all of which are considered as risk factors for type 2 diabetes mellitus (T2DM) and cardiovascular diseases, which are associated in turn with an increase of OxS. In this sense, we review scientific evidence that supports the association between OxS with telomere length (TL) dynamics and the relationship with MetS components in aging. It was analysed whether each MetS component affects the telomere length separately or if they all affect it together. Likewise, this review provides a summary of the structure and function of telomeres and telomerase, the mechanisms of telomeric DNA repair, how telomere length may influence the fate of cells or be linked to inflammation and the development of age-related diseases, and finally, how the lifestyles can affect telomere length.


2018 ◽  
Vol 25 (11) ◽  
pp. 1294-1310 ◽  
Author(s):  
Raffaella Mastrocola ◽  
Manuela Aragno ◽  
Giuseppe Alloatti ◽  
Massimo Collino ◽  
Claudia Penna ◽  
...  

In the last decades, the extension of life expectancy and the increased consumption of foods rich in saturated fats and added sugars have exposed the general population to emerging health problems. The prevalence of metabolic syndrome (MS), composed of a cluster of factors as obesity, dyslipidemia, hyperglycemia, and hypertension, is rapidly increasing in industrialized and developing countries leading to precocious onset of age-related diseases. Indeed, oxidative stress, accumulation of advanced glycation endproducts, and a chronic low-grade inflammation are common features of MS and physiological ageing. In particular, the entire set of MS factors contributes to the development of an inflammatory status named metaflammation, which has been associated with activation of early innate immune response through the assembling of the multiprotein complex inflammasome. The most investigated family of inflammasome platforms is the NOD-like receptor pyridine containing (NLRP) 3, which is activated by several exogenous and endogenous stimuli, leading to the sequential cleavage of caspase-1 and IL-1β, followed by secretion of active IL-1β. We here collect the most recent findings on NLRP3 activation in MS providing evidence of its central role in disease progression and organ dysfunction in target tissues of metaflammation, in particular in cardiovascular, hepatic and renal complications, with a focus on oxidative stress and advanced glycation endproducts. A wide overview of the most promising strategies for the modulation of NLRP3 activation and related metabolic repercussions is also provided, since the finding of specific pharmacological tools is an urgent requirement to reduce the social and economic burden of MS- and elderly-associated diseases.


2018 ◽  
Vol 20 (1) ◽  
pp. 106 ◽  
Author(s):  
Satomi Kagota ◽  
Kana Maruyama-Fumoto ◽  
Saki Iwata ◽  
Miho Shimari ◽  
Shiori Koyanagi ◽  
...  

Perivascular adipose tissue (PVAT) can regulate vascular tone. In mesenteric arteries of SHRSP.Z-Leprfa/IzmDmcr rats (SHRSP.ZF) with metabolic syndrome, vascular dysfunction is compensated by PVAT-dependent mechanisms that disappear with increasing age. In this study, we investigated the mechanisms of the age-related changes and responsible factor(s) involved in the enhancing effects of mesenteric arterial PVAT in SHRSP.ZF. Acetylcholine- and sodium nitroprusside-induced relaxations of isolated arteries were greater with PVAT than without PVAT at 17 and 20 weeks of age (wks), and as expected, this enhancement by the presence of PVAT disappeared at 23 wks. PVAT mRNA levels of angiotensin II type 1 (AT1) receptor-associated protein was less and AT1 receptor was unchanged at 23 wks when compared to 20 wks. At 20 wks, the enhanced acetylcholine-induced relaxation by the presence of PVAT was inhibited by N-acetyl-l-cysteine (NAC). Acetylcholine-induced relaxation of arteries without PVAT was increased in the presence of exogenously added apelin. PVAT mRNA level of apelin was higher in SHRSP.ZF than in control Wistar-Kyoto rats, and the level was decreased with aging. These results suggest that AT1 receptor activation in PVAT, and changes in the regulation of apelin and a NAC-sensitive factor are related to the age-dependent deterioration of the vasodilation enhancing effects of mesenteric arterial PVAT in SHRSP.ZF.


2008 ◽  
pp. S49-S54
Author(s):  
E Babušíková ◽  
M Jeseňák ◽  
D Dobrota ◽  
N Tribulová ◽  
P Kaplán

The oxidative stress hypothesis of aging suggests that accumulation of oxidative damage is a key factor of the alterations in physiological function during aging. We studied age-related sensitivity to oxidative modifications of proteins and lipids of cardiac sarcoplasmic reticulum (SR) isolated from 6-, 15- and 26-month-old rats. Oxidative stress was generated in vitro by exposing SR vesicles to 0.1 mmol/l FeSO4/EDTA + 1 mmol/l H2O2 at 37 degrees C for 60 min. In all groups, oxidative stress was associated with decreased membrane surface hydrophobicity, as detected by 1-anilino-8-naphthalenesulfonate as a probe. Structural changes in SR membranes were accompanied by degradation of tryptophan and significant accumulation of protein dityrosines, protein conjugates with lipid peroxidation products, conjugated dienes and thiobarbituric acid reactive substances. The sensitivity to oxidative damage was most pronounced in SR of 26-month-old rat. Our results indicate that aging and oxidative stress are associated with accumulation of oxidatively damaged proteins and lipids and these changes could contribute to cardiovascular injury.


2020 ◽  
Vol 70 (5) ◽  
pp. 329-334
Author(s):  
Charles R Powell ◽  
Albert Kim ◽  
Joshua Roth ◽  
James P Byrd ◽  
Khalid Mohammad ◽  
...  

Metabolic Syndrome (MetS) has detrimental effects on the bladder, including detrusor underactivity. The progression and mechanism of disease are poorly understood. A swine model for diabetic bladder dysfunction (DBD) was established because of the pig's human-sized bladder and its ability to develop MetS by dietary modification alone. The hypothesis of this study is that this swine model will demonstrate oxidative stress associated with MetS, which contributes to both bladder fibrosis and detrusor underactivity (DU). Ossabaw pigs underwent dietary modification consisting of a hypercaloric, atherogenic diet for 10 mo to induce MetS, and were compared with a group of control (lean) pigs. Urodynamic studies were performed in both groups to confirm DU. Thiobarbituric acid reactive substances (TBARS) detected in the urine were used to measure oxidative stress activity in the urinary tract, and urinary IL17a was used to detect profibrotic activity. MetS was confirmed by assessing body weight, blood pressure, glucose tolerance, total cholesterol, and triglycerides. The MetS group exhibited an increase in the relative levels of urinary TBARS and IL17a. Bladder pressures at capacity were lower in the MetS group, suggesting DU. Histologic analysis of a cohort of control (lean) and MetS pigs revealed that as compared with the control pigs, the MetS pigs had significantly more collagen in the muscularis layer, but not in the submucosa or mucosa layer. In conclusion, the Ossabaw pig model for diet-induced MetS is associated with oxidative stress and profibrotic activity in the bladder, which results in DU. This has previously been shown in mice and rats, but never in pigs. This novel model will better represent human MetS and DBD because the mechanism and size of the pig bladder more closely resemble that of a human, resulting in a more valid model and facilitating further study into the signaling mechanisms responsible for this impairment.


2009 ◽  
Vol 2 (1) ◽  
pp. 141-148 ◽  
Author(s):  
Alexandra A. Herzlich ◽  
Xiaoyan Ding ◽  
Defen Shen ◽  
Robert J. Ross ◽  
Jingsheng Tuo ◽  
...  

Peroxisome proliferator-activated receptors (PPARs) play a role in oxidative stress and VEGF regulation, which are closely related to age-related macular degeneration (AMD). PPAR γ expression and its downstream molecules were examined in fat-1 mice (transgenic mice that convert n-6 to n-3 fatty acids), Ccl2-/-/Cx3cr1-/- mice (an AMD model), ARPE19 cells (a human retinal pigment epithelial cell line, RPE, a cell type with a critical role in AMD), and human eyes with and without AMD. PPAR α, β, and γ, VEGF and receptors were determined by immunohistochemistry in the mice models, humans, and ARPE19 cells. Transcripts of PPARs, VEGF, MMP-9 and HO-1 were determined by RQ-PCR. PPARs were constitutively expressed in normal neuroretina and RPE of humans and mice. PPAR γ expression was increased in fat-1 and Ccl2-/-/Cx3cr1-/- mice. VEGF was decreased in fat-1 mice but increased in Ccl2-/-/Cx3cr1-/- mice. VEGF receptors were stable. VEGF, MMP9 and HO-1 transcript levels were increased in ARPE19 cells under H2O2 - induced oxidative stress. Human AMD retinas exhibited higher PPAR γ. The findings of increased expression of PPAR γ and its downstream proteins (VEGF, MMP9, and HO-1) in H2O2-treated ARPE19 cells, Ccl2-/-/Cx3cr1-/- mice, and human AMD eyes, but decreased VEGF in fat-1 mice, suggest that PPAR γ may play a role in AMD.


2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Samuel Abokyi ◽  
Sze wan Shan ◽  
Chi-ho To ◽  
Henry Ho-lung Chan ◽  
Dennis Yan-yin Tse

Trehalose is a natural dietary molecule that has shown antiaging and neuroprotective effects in several animal models of neurodegenerative diseases. The role of trehalose in the management of age-related macular degeneration (AMD) is yet to be investigated and whether trehalose could be a remedy for the treatment of diseases linked to oxidative stress and NRF2 dysregulation. Here, we showed that incubation of human retinal pigment epithelial (RPE) cells with trehalose enhanced the mRNA and protein expressions of TFEB, autophagy genes ATG5 and ATG7, as well as protein expressions of macroautophagy markers, LC3B and p62/SQTM1, and the chaperone-mediated autophagy (CMA) receptor LAMP2. Cathepsin D, a hydrolytic lysosomal enzyme, was also increased by trehalose, indicating higher proteolytic activity. Moreover, trehalose upregulated autophagy flux evident by an increase in the endogenous LC3B level, and accumulation of GFP-LC3B puncta and free GFP fragments in GFP-LC3 ̶ expressing cells in the presence of chloroquine. In addition, the mRNA levels of key molecular targets implicated in RPE damage and AMD, such as vascular endothelial growth factor- (VEGF-) A and heat shock protein 27 (HSP27), were downregulated, whereas NRF2 was upregulated by trehalose. Subsequently, we mimicked in vitro AMD conditions using hydroquinone (HQ) as the oxidative insult on RPE cells and evaluated the cytoprotective effect of trehalose compared to vehicle treatment. HQ depleted NRF2, increased oxidative stress, and reduced the viability of cells, while trehalose pretreatment protected against HQ-induced toxicity. The cytoprotection by trehalose was dependent on autophagy but not NRF2 activation, since autophagy inhibition by shRNA knockdown of ATG5 led to a loss of the protective effect. The results support the transcriptional upregulation of TFEB and autophagy by trehalose and its protection against HQ-induced oxidative damage in RPE cells. Further investigation is, therefore, warranted into the therapeutic value of trehalose in alleviating AMD and retinal diseases associated with impaired NRF2 antioxidant defense.


1997 ◽  
Vol 43 (7) ◽  
pp. 1209-1214 ◽  
Author(s):  
Flemming Nielsen ◽  
Bo Borg Mikkelsen ◽  
Jesper Bo Nielsen ◽  
Helle Raun Andersen ◽  
Philippe Grandjean

Abstract Malondialdehyde (MDA) is one of the most frequently used indicators of lipid peroxidation. To generate reliable reference intervals for plasma malondialdehyde (P-MDA), a reference sample group was established in Funen, Denmark. The group consisted of 213 individuals (107 men, 106 women), ages 20–79 years. P-MDA was measured in EDTA-treated plasma after derivatization by thiobarbituric acid (TBA) and separation on HPLC. UV detection was performed at 532 nm. A reference interval was calculated as recommended by IFCC with REFVAL 3.42. The estimated reference limits (0.025 and 0.975 fractals) for the group were 0.36 and 1.24 μmol/L. The data were analyzed for gender- and age-related differences. Analysis of variance showed no interaction between gender and age, but separate analyses showed an independent effect of gender (P = 0.03), but not of age (P = 0.11). Daily smokers had a slightly higher average concentration of P-MDA than nonsmokers (P = 0.05), and P-MDA correlated with daily exposure to cigarette smoke (r = 0.162; P = 0.03). A positive correlation was also demonstrated between P-MDA and weekly alcohol consumption (r = 0.153; P = 0.03). Within-subject and day-to-day variations of P-MDA indicated that the potential of P-MDA as a biomarker for individuals is questionable. However, on a group basis, the present data support that P-MDA may be a potential biomarker for oxidative stress.


Cells ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 2346
Author(s):  
Aline Yammine ◽  
Amira Zarrouk ◽  
Thomas Nury ◽  
Anne Vejux ◽  
Norbert Latruffe ◽  
...  

The Mediterranean diet is associated with health benefits due to bioactive compounds such as polyphenols. The biological activities of three polyphenols (quercetin (QCT), resveratrol (RSV), apigenin (API)) were evaluated in mouse neuronal N2a cells in the presence of 7-ketocholesterol (7KC), a major cholesterol oxidation product increased in patients with age-related diseases, including neurodegenerative disorders. In N2a cells, 7KC (50 µM; 48 h) induces cytotoxic effects characterized by an induction of cell death. When associated with RSV, QCT and API (3.125; 6.25 µM), 7KC-induced toxicity was reduced. The ability of QCT, RSV and API to prevent 7KC-induced oxidative stress was characterized by a decrease in reactive oxygen species (ROS) production in whole cells and at the mitochondrial level; by an attenuation of the increase in the level and activity of catalase; by attenuating the decrease in the expression, level and activity of glutathione peroxidase 1 (GPx1); by normalizing the expression, level and activity of superoxide dismutases 1 and 2 (SOD1, SOD2); and by reducing the decrease in the expression of nuclear erythroid 2-like factor 2 (Nrf2) which regulates antioxidant genes. QCT, RSV and API also prevented mitochondrial dysfunction in 7KC-treated cells by counteracting the loss of mitochondrial membrane potential (ΨΔm) and attenuating the decreased gene expression and/or protein level of AMP-activated protein kinase α (AMPKα), sirtuin 1 (SIRT1) and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) implicated in mitochondrial biogenesis. At the peroxisomal level, QCT, RSV and API prevented the impact of 7KC by counteracting the decrease in ATP binding cassette subfamily D member (ABCD)3 (a peroxisomal mass marker) at the protein and mRNA levels, as well as the decreased expresssion of genes associated with peroxisomal biogenesis (Pex13, Pex14) and peroxisomal β-oxidation (Abcd1, Acox1, Mfp2, Thiolase A). The 7KC-induced decrease in ABCD1 and multifunctional enzyme type 2 (MFP2), two proteins involved in peroxisomal β-oxidation, was also attenuated by RSV, QCT and API. 7KC-induced cell death, which has characteristics of apoptosis (cells with fragmented and/or condensed nuclei; cleaved caspase-3; Poly(ADP-ribose) polymerase (PARP) fragmentation) and autophagy (cells with monodansyl cadaverine positive vacuoles; activation of microtubule associated protein 1 light chain 3–I (LC3-I) to LC3-II, was also strongly attenuated by RSV, QCT and API. Thus, in N2a cells, 7KC induces a mode of cell death by oxiapoptophagy, including criteria of OXIdative stress, APOPTOsis and autoPHAGY, associated with mitochondrial and peroxisomal dysfunction, which is counteracted by RSV, QCT, and API reinforcing the interest for these polyphenols in prevention of diseases associated with increased 7KC levels.


2007 ◽  
Vol 21 (11) ◽  
pp. 2605-2614 ◽  
Author(s):  
Stavros C. Manolagas ◽  
Maria Almeida

Abstract The Wnt/β-catenin signaling pathway affects several biological processes ranging from embryonic development, patterning, and postembryonic stem cell fate, to bone formation and insulin secretion in adulthood. β-Catenin mediates canonical Wnt signaling by binding to and activating members of the T-cell factor (TCF) transcription factor family. Similar to the Wnt/β-catenin pathway, oxidative stress influences fundamental cellular processes including stem cell fate and has been linked to aging and the development of age-related diseases. However, the molecular details of the pathogenetic effects of oxidative stress on the homeostasis of many different tissues remain unclear. β-Catenin has been recently implicated as a pivotal molecule in defense against oxidative stress by serving as a cofactor of the forkhead box O (FOXO) transcription factors. In addition, it has been shown that oxidative stress is a pivotal pathogenetic factor of age-related bone loss and strength in mice, leading to, among other changes, a decrease in osteoblast number and bone formation. These particular cellular changes evidently result from diversion of the limited pool of β-catenin from TCF- to FOXO-mediated transcription in osteoblastic cells. Fascinatingly, attenuation of Wnt-mediated transcription, resulting from an autosomal-dominant missense mutation in LRP6, a coreceptor for the Wnt-signaling pathway, has been linked recently genetically not only to premature osteoporosis, but also to coronary artery disease as well as several features of the metabolic syndrome including hyperlipidemia, hypertension, and diabetes, but not obesity. In this minireview, we highlight evidence linking the age-associated oxidative stress with FOXOs, Wnt/β-catenin signaling, osteoblastogenesis, adipogenesis, osteoporosis, and several features of the metabolic syndrome. We hypothesize that antagonism of Wnt signaling by oxidative stress with increasing age may be a common molecular mechanism contributing to the development not only of involutional osteoporosis, but several pathologies such as atherosclerosis, insulin resistance, and hyperlipidemia, all of which become more prevalent with advancing age.


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