Endothelin-1 downregulates nuclear factor erythroid 2-related factor-2 and contributes to perivascular adipose tissue dysfunction in obesity.

Perivascular adipose tissue (PVAT) negatively regulates vascular muscle contraction. However, in the context of obesity, the PVAT releases vasoconstrictor substances that detrimentally affect vascular function. A pivotal player in this scenario is the peptide endothelin-1 (ET-1), which induces oxidative stress and disrupts vascular function. This study postulates that obesity augments ET-1 production in the PVAT, decreases the function of the nuclear factor erythroid 2-related factor-2 (Nrf2) transcription factor, further increasing reactive oxygen species (ROS) generation, culminating in PVAT dysfunction. Male C57BL/6 mice were fed either a standard or a high-fat diet for 16 weeks. Mice were also treated with saline or a daily dose of 100 mg.kg-1 of the ETA and ETB receptor antagonist Bosentan, for 7 days. Vascular function was evaluated in thoracic aortic rings, with and without PVAT. Mechanistic studies utilized PVAT from all groups and cultured WT-1 mouse brown adipocytes. PVAT from obese mice exhibited increased ET-1 production, increased ECE1 and ETA gene expression, loss of the anticontractile effect, as well as increased ROS production, decreased Nrf2 activity, and downregulated expression of Nrf2-targeted antioxidant genes. PVAT of obese mice also exhibited increased expression of Tyr216-phosphorylated-GSK3ß and KEAP1, but not BACH1 - negative Nrf2 regulators. Bosentan treatment reversed all these effects. Similarly, ET-1 increased ROS generation and decreased Nrf2 activity in brown adipocytes, events mitigated by BQ123 (ETA receptor antagonist). These findings place ET-1 as a major contributor to PVAT dysfunction in obesity and highlight that pharmacological control of ET-1 effects restores PVAT's cardiovascular protective role.

NADPH oxidase 4-derived hydrogen peroxide counterbalances testosterone-induced endothelial dysfunction and migration.

High levels of testosterone (Testo) are associated with cardiovascular risk by increasing reactive oxygen species (ROS) formation. NADPH oxidases (NOX) are the major source of ROS in the vasculature of cardiovascular diseases. NOX4 is a unique isotype, which produces hydrogen peroxide (H2O2), and its participation in cardiovascular biology is controversial. So far, it is unclear whether NOX4 protects from Testo-induced endothelial injury. Thus, we hypothesized that supraphysiological levels of Testo induce endothelial NOX4 expression to attenuate endothelial injury. Human mesenteric vascular endothelial cells (HMECs) and human umbilical vein endothelial cells (HUVEC) were treated with Testo (10-7 M) with or without a NOX4 inhibitor [GLX351322 (10-4 M)] or NOX4 siRNA. In vivo, 10-wk-old C57Bl/6J male mice were treated with Testo (10 mg/kg) for 30 days to study endothelial function. Testo increased mRNA and protein levels of NOX4 in HMECs and HUVECs. Testo increased superoxide anion (O2-) and H2O2 production, which were abolished by NOX1 and NOX4 inhibition, respectively. Testo also attenuated bradykinin-induced NO production, which was further impaired by NOX4 inhibition. In vivo, Testo decreased H2O2 production in aortic segments and triggered endothelial dysfunction [decreased relaxation to acetylcholine (ACh)], which was further impaired by GLX351322 and by a superoxide dismutase and catalase mimetic (EUK134). Finally, Testo led to a dysregulated endothelial cell migration, which was exacerbated by GLX351322. These data indicate that supraphysiological levels of Testo increase the endothelial expression and activity of NOX4 to counterbalance the deleterious effects caused by Testo in endothelial function.NEW & NOTEWORTHY By inducing ROS formation, high levels of testosterone play a major role in the pathogenesis of cardiovascular disease. NOXs are the major sources of ROS in the vasculature of cardiovascular diseases. Herein, we describe a novel compensatory mechanism by showing that NOX4 is a protective oxidant enzyme and counterbalances the deleterious effects of testosterone in endothelial cells by modulating hydrogen peroxide formation.

In utero exposure to maternal diabetes exacerbates dietary sodium intake-induced endothelial dysfunction by activating cyclooxygenase 2-derived prostanoids.

Prenatal exposure to maternal diabetes has been recognized as a significant cardiovascular risk factor, increasing the susceptibility to the emergence of conditions such as high blood pressure, atherosclerosis, and heart disease in later stages of life. However, it is unclear if offspring exposed to diabetes in utero have worse vascular outcomes on a high-salt (HS) diet. To test the hypothesis that in utero exposure to maternal diabetes predisposes to HS-induced vascular dysfunction, we treated adult male wild-type offspring (DM_Exp, 6 mo old) of diabetic Ins2+/C96Y mice (Akita mice) with HS (8% sodium chloride, 10 days) and analyzed endothelial function via wire myograph and cyclooxygenase (COX)-derived prostanoids pathway by ELISA, quantitative PCR, and immunochemistry. On a regular diet, DM_Exp mice did not manifest any vascular dysfunction, remodeling, or inflammation. However, HS increased aortic contractility to phenylephrine and induced endothelial dysfunction (analyzed by acetylcholine-induced endothelium-dependent relaxation), vascular hydrogen peroxide production, COX2 expression, and prostaglandin E2 (PGE2) overproduction. Interestingly, ex vivo antioxidant treatment (tempol) or COX1/2 (indomethacin) or COX2 (NS398) inhibitors improved or reverted the endothelial dysfunction in DM_Exp mice fed a HS diet. Finally, DM_Exp mice fed with HS exhibited greater circulating cytokines and chemokines accompanied by vascular inflammation. In summary, our findings indicate that prenatal exposure to maternal diabetes predisposes to HS-induced vascular dysfunction, primarily through the induction of oxidative stress and the generation of COX2-derived PGE2. This supports the concept that in utero exposure to maternal diabetes is a cardiovascular risk factor in adulthood.NEW & NOTEWORTHY Using a unique mouse model of prenatal exposure to maternal type 1 diabetes, our study demonstrates the novel observation that prenatal exposure to maternal diabetes results in a predisposition to high-salt (HS) dietary-induced vascular dysfunction and inflammation in adulthood. Mechanistically, we demonstrated that in utero exposure to maternal diabetes and HS intake induces vascular oxidative stress, cyclooxygenase-derived prostaglandin E2, and inflammation.

Role of the CCL5 and Its Receptor, CCR5, in the Genesis of Aldosterone-Induced Hypertension, Vascular Dysfunction, and End-Organ Damage.

BACKGROUND: Aldosterone has been described to initiate cardiovascular diseases by triggering exacerbated sterile vascular inflammation. The functions of CCL5 (C-C motif chemokine ligand 5) and its receptor CCR5 (C-C motif chemokine receptor 5) are well known in infectious diseases, their contributions to aldosterone-induced vascular injury and hypertension remain unknown. METHODS: We analyzed the vascular profile, blood pressure, and renal damage in wild-type (CCR5+/+) and CCR5 knockout (CCR5-/-) mice treated with aldosterone (600 µg/kg per day for 14 days) while receiving 1% saline to drink. Vascular function was analyzed in aorta and mesenteric arteries, blood pressure was measured by telemetry and renal injury and inflammation were analyzed via histology and flow cytometry. Endothelial cells were used to study the molecular signaling whereby CCL5 induces endothelial dysfunction. RESULTS: Aldosterone treatment resulted in exaggerated CCL5 circulating levels and vascular CCR5 expression in CCR5+/+ mice accompanied by endothelial dysfunction, hypertension, and renal inflammation and damage. CCR5-/- mice were protected from these aldosterone-induced effects. Mechanistically, we demonstrated that CCL5 increased NOX1 (NADPH oxidase 1) expression, reactive oxygen species formation, NFκB (nuclear factor kappa B) activation, and inflammation and reduced NO production in isolated endothelial cells. These effects were abolished by antagonizing CCR5 with Maraviroc. Finally, aorta incubated with CCL5 displayed severe endothelial dysfunction, which is prevented by blocking NOX1, NFκB, or CCR5. CONCLUSIONS: Our data demonstrate that CCL5/CCR5, through activation of NFκB and NOX1, is critically involved in aldosterone-induced vascular and renal damage and hypertension placing CCL5 and CCR5 as potential therapeutic targets for conditions characterized by aldosterone excess.

Monitoring phosphorylation and acetylation of CRISPR-mediated HiBiT-tagged endogenous proteins.

Intracellular pathways transduce signals through changes in post-translational modifications (PTMs) of effector proteins. Among the approaches used to monitor PTM changes are immunoassays and overexpression of recombinant reporter genes. Genome editing by CRISPR/Cas9 provides a new means to monitor PTM changes by inserting reporters onto target endogenous genes while preserving native biology. Ideally, the reporter should be small in order not to interfere with the processes mediated by the target while sensitive enough to detect tightly expressed proteins. HiBiT is a 1.3 kDa reporter peptide capable of generating bioluminescence through complementation with LgBiT, an 18 kDa subunit derived from NanoLuc. Using HiBiT CRISPR/Cas9-modified cell lines in combination with fluorescent antibodies, we developed a HiBiT-BRET immunoassay (a.k.a. Immuno-BRET). This is a homogeneous immunoassay capable of monitoring post-translational modifications on diverse protein targets. Its usefulness was demonstrated for the detection of phosphorylation of multiple signaling pathway targets (EGFR, STAT3, MAPK8 and c-MET), as well as chromatin containing histone H3 acetylation on lysine 9 and 27. These results demonstrate the ability to efficiently monitor endogenous biological processes modulated by post-translational modifications using a small bioluminescent peptide tag and fluorescent antibodies, providing sensitive quantitation of the response dynamics to multiple stimuli.

Pharmacological activation of nuclear factor erythroid 2-related factor-2 prevents hyperglycemia-induced renal oxidative damage: Possible involvement of O-GlcNAcylation.

Hyperglycemia is a major risk factor for kidney diseases. Oxidative stress, caused by reactive oxygen species, is a key factor in the development of kidney abnormalities related to hyperglycemia. The nuclear factor erythroid 2-related factor-2 (Nrf2) plays a crucial role in defending cells against oxidative stress by activating genes that produce antioxidants. L-sulforaphane (SFN), a drug that activates Nrf2, reduces damage caused by hyperglycemia. Hyperglycemic Wistar rats and HEK 293 cells maintained in hyperglycemic medium exhibited decreased Nrf2 nuclear translocation and reduced expression and activity of antioxidant enzymes. SFN treatment increased Nrf2 activity and reversed decreased renal function, oxidative stress and cell death associated with hyperglycemia. To investigate mechanisms involved in hyperglycemia-induced reduced Nrf2 activity, we addressed whether Nrf2 is modified by O-linked ß-N-acetylglucosamine (O-GlcNAc), a post-translational modification that is fueled in hyperglycemic conditions. In vivo, hyperglycemia increased O-GlcNAc-modified Nrf2 expression. Increased O-GlcNAc levels, induced by pharmacological inhibition of OGA, decreased Nrf2 activity in HEK 293 cells. In conclusion, hyperglycemia reduces Nrf2 activity, promoting oxidative stress, cell apoptosis and structural and functional renal damage. Pharmacological treatment with SFN attenuates renal injury. O-GlcNAcylation negatively modulates Nrf2 activity and represents a potential mechanism leading to oxidative stress and renal damage in hyperglycemic conditions.

Atorvastatina Atenua o Remodelamento Vascular em Camundongos com Síndrome Metabólica / Atorvastatin Attenuates Vascular Remodeling in Mice with Metabolic Syndrome

Resumo Fundamento A síndrome metabólica é caracterizada por um conjunto de comorbidades. Durante a síndrome, observam-se alterações estruturais no sistema cardiovascular, especialmente o remodelamento vascular. Uma das causas predisponentes para essas alterações é a inflamação crônica oriunda de mudanças na estrutura e composição do tecido adiposo perivascular. Atorvastatina é eficaz no tratamento das dislipidemias. No entanto, seus efeitos pleiotrópicos não são totalmente compreendidos. Supõe-se que, durante a síndrome metabólica, ocorre remodelamento vascular e que o tratamento com atorvastatina pode ser capaz de atenuar tal condição. Objetivos Avaliar os efeitos do tratamento com atorvastatina sobre o remodelamento vascular em modelo experimental de síndrome metabólica. Métodos Camundongos Swiss receberam dieta controle ou dieta hiperglicídica por 18 semanas. Após 14 semanas de dieta, os camundongos foram tratados com veículo ou atorvastatina (20mg/kg) durante 4 semanas. Foram avaliados o perfil nutricional e metabólico por testes bioquímicos; análise estrutural da artéria aorta por histologia e dosagem de citocinas por ensaio imunoenzimático. O nível de significância aceitável para os resultados foi p <0,05. Resultados A dieta hiperglicídica promoveu o desenvolvimento de síndrome metabólica. Tal fato culminou no remodelamento hipertrófico do músculo liso vascular e tecido adiposo perivascular. Além disso, houve aumentos das citocinas TNF-α e IL-6 circulantes e no tecido adiposo perivascular. O tratamento com atorvastatina reduziu significativamente os danos metabólicos, o remodelamento vascular e os níveis de citocinas. Conclusão Atorvastatina ameniza danos metabólicos associados à síndrome metabólica induzida por dieta hiperglicídica, além de atenuar o remodelamento vascular, sendo esses efeitos associados à redução de citocinas pró-inflamatórias.

Abstract Background Metabolic syndrome is characterized by an array of comorbidities. During this syndrome, structural changes are observed in the cardiovascular system, especially vascular remodeling. One of the predisposing causes for these changes is chronic inflammation resulting from changes in the structure and composition of perivascular adipose tissue. Atorvastatin is effective in the treatment of dyslipidemias. However, its pleiotropic effects have not been completely understood. We hypothesize that metabolic syndrome may lead to vascular remodeling and that atorvastatin therapy may be able to attenuate this condition. Objectives To assess the effects of atorvastatin therapy on vascular remodeling in an experimental model of metabolic syndrome. Methods Swiss mice received a control diet or a hyperglicemic diet for 18 weeks. After 14 weeks of diet, mice were treated with vehicle or atorvastatin (20mg/kg) during for 4 weeks. Nutritional and metabolic profiles were assessed by biochemical tests; moreover, a histological assessment of aorta structure was conducted, and cytokine levels were determined by the immunoenzyme assay. The acceptable level of significance for the results was set at p<0.05. Results Hyperglicemic diet promoted the development of metabolic syndrome. It indeed culminated in hypertrophic remodeling of vascular smooth muscle and perivascular adipose tissue. Furthermore, there were increases in the levels of circulating TNF-α and IL-6 and in the perivascular adipose tissue. Atorvastatin therapy significantly reduced metabolic damages, vascular remodeling, and cytokine levels. Conclusion Atorvastatin attenuate metabolic damages associated with metabolic syndrome induced by hyperglycemic diet, in addition to attenuating vascular remodeling; both effects are associated with reduced levels of pro-inflammatory cytokines.

Avaliação microscópica do desgaste superficial do esmalte dental. Efeito da aplicação de diferentes pastas microabrasivas / Enamel tooth removal by using microabrasion technique. Effects of microabrasive products

A realização deste trabalho teve como objetivo avaliar, in vitro, a quantidade de esmalte dental removido após o emprego da técnica de microabrasão. Neste experimento, foram empregados o ácido fosfórico a 37% associado a pedra-pomes de granulometria extrafina e o produto microabrasivo Prema Compound (Premier Dental Company). Após a realização da técnica microabrasiva, as coroas dentais foram seccionadas no sentido transversal, obtendo-se duas fatias dentais que foram, em seguida, lixadas até a espessura de 100mm. Os cortes por desgaste dos espécimes foram, então, examinados ao microscópio óptico comum, sob ação de luz polarizada, em aumento de 100x, momento em que foram realizadas as mensurações, em micrômetros, da quantidade de esmalte desgastado. Concluímos que a microabrasão do esmalte dental com a pasta de pedra-pomes de granulometria extrafina associada ao ácido fosfórico a 37% foi capaz de promover um maior desgaste da superfície adamantina que o produto Prema Compound (Premier Dental Company), nos tempos analisados