The evolutionary conserved miR-137/325 tandem mediates obesity-induced hypogonadism and metabolic comorbidities by repressing hypothalamic kisspeptin.

BACKGROUND: Obesity-induced hypogonadism (OIH) is a prevalent, but often neglected condition in men, which aggravates the metabolic complications of overweight. While hypothalamic suppression of Kiss1-encoded kisspeptin has been suggested to contribute to OIH, the molecular mechanisms for such repression in obesity, and the therapeutic implications thereof, remain unknown. METHODS: A combination of bioinformatic, expression and functional analyses was implemented, assessing the role of the evolutionary-conserved miRNAs, miR-137 and miR-325, in mediating obesity-induced suppression of hypothalamic kisspeptin, as putative mechanism of central hypogonadism and metabolic comorbidities. The implications of such miR-137/325-kisspeptin interplay for therapeutic intervention in obesity were also explored using preclinical OIH models. RESULTS: MiR-137/325 repressed human KISS1 3'-UTR in-vitro and inhibited hypothalamic kisspeptin content in male rats, while miR-137/325 expression was up-regulated, and Kiss1/kisspeptin decreased, in the medio-basal hypothalamus of obese rats. Selective over-expression of miR-137 in Kiss1 neurons reduced Kiss1/ kisspeptin and partially replicated reproductive and metabolic alterations of OIH in lean mice. Conversely, interference of the repressive actions of miR-137/325 selectively on Kiss1 3'-UTR in vivo, using target-site blockers (TSB), enhanced kisspeptin content and reversed central hypogonadism in obese rats, together with improvement of glucose intolerance, insulin resistance and cardiovascular and inflammatory markers, despite persistent exposure to obesogenic diet. Reversal of OIH by TSB miR-137/325 was more effective than chronic kisspeptin or testosterone treatments in obese rats. CONCLUSIONS: Our data disclose that the miR-137/325-Kisspeptin repressive interaction is a major player in the pathogenesis of obesity-induced hypogonadism and a putative druggable target for improved management of this condition and its metabolic comorbidities in men suffering obesity. SIGNIFICANCE STATEMENT: Up to half of the men suffering obesity display also central hypogonadism, an often neglected complication of overweight that can aggravate the clinical course of obesity and its complications. The mechanisms for such obesity-induced hypogonadism remain poorly defined. We show here that the evolutionary conserved miR137/miR325 tandem centrally mediates obesity-induced hypogonadism via repression of the reproductive-stimulatory signal, kisspeptin; this may represent an amenable druggable target for improved management of hypogonadism and other metabolic complications of obesity.

Resolvin D2 prevents vascular remodeling, hypercontractility and endothelial dysfunction in obese hypertensive mice through modulation of vascular and proinflammatory factors.

During resolution of inflammation, specialized proresolving mediators (SPMs), including resolvins, are produced to restore tissue homeostasis. We hypothesized that there might be a dysregulation of SPMs pathways in pathological vascular remodeling and that resolvin D2 (RvD2) might prevent vascular remodeling and contractile and endothelial dysfunction in a model of obesity and hypertension. In aortic samples of patients with or without abdominal aortic aneurysms (AAA), we evaluated gene expression of enzymes involved in SPMs synthesis (ALOXs), SPMs receptors and pro-inflammatory genes. In an experimental model of aortic dilation induced by high fat diet (HFD, 60%, eighteen weeks) and angiotensin II (AngII) infusion (four weeks), we studied the effect of RvD2 administration in aorta and small mesenteric arteries structure and function and markers of inflammation. In human macrophages we evaluated the effects of AngII and RvD2 in macrophages function and SPMs profile. In patients, we found positive correlations between AAA and obesity, and between AAA and expression of ALOX15, RvD2 receptor GPR18, and pro-inflammatory genes. There was an inverse correlation between the expression of aortic ALOX15 and AAA growth rate. In the mice model, RvD2 partially prevented the HFD plus AngII-induced obesity and adipose tissue inflammation, hypertension, aortic and mesenteric arteries remodeling, hypercontratility and endothelial dysfunction, and the expression of vascular proinflammatory markers and cell apoptosis. In human macrophages, RvD2 prevented AngII-induced impaired efferocytosis and switched SPMs profile. RvD2 might represent a novel protective strategy in preventing vascular damage associated to hypertension and obesity likely through effects in vascular and immune cells.

Immunomodulatory Activity of Cytokines in Hypertension: A Vascular Perspective.

Cytokines play a crucial role in the structure and function of blood vessels in hypertension. Hypertension damages blood vessels by mechanisms linked to shear forces, activation of the renin-angiotensin-aldosterone and sympathetic nervous systems, oxidative stress, and a proinflammatory milieu that lead to the generation of neoantigens and damage-associated molecular patterns, ultimately triggering the release of numerous cytokines. Damage-associated molecular patterns are recognized by PRRs (pattern recognition receptors) and activate inflammatory mechanisms in endothelial cells, smooth muscle cells, perivascular nerves, and perivascular adipose tissue. Activated vascular cells also release cytokines and express factors that attract macrophages, dendritic cells, and lymphocytes to the blood vessels. Activated and differentiated T cells into Th1, Th17, and Th22 in secondary lymphoid organs migrate to the vessels, releasing specific cytokines that further contribute to vascular dysfunction and remodeling. This chronic inflammation alters the profile of endothelial and smooth muscle cells, making them dysfunctional. Here, we provide an overview of how cytokines contribute to hypertension by impacting the vasculature. Furthermore, we explore clinical perspectives about the modulation of cytokines as a potential therapeutic intervention to specifically target hypertension-linked vascular dysfunction.

The Melatonin Derivative ITH13001 Prevents Hypertension and Cardiovascular Alterations in Angiotensin II-Infused Mice.

Inflammatory mechanisms and oxidative stress seem to contribute to the pathogenesis of hypertension. ITH13001 is a melatonin-phenyl-acrylate hybrid that moderately induces the antioxidant transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2) and has a potent oxidant scavenging effect compared with other derivatives of its family. Here we investigated the effect of ITH13001 on hypertension and the associated cardiovascular alterations. Angiotensin II (AngII)-infused mice were treated with ITH13001 (1 mg/kg per day, i.p.) for 2 weeks. The ITH13001 treatment prevented: 1) the development of hypertension, cardiac hypertrophy, and increased collagen and B-type natriuretic peptide (Bnp) expression in the heart; 2) the reduction of elasticity, incremental distensibility, fenestrae area, intraluminal diameter, and endothelial cell number in mesenteric resistance arteries (MRA); 3) the endothelial dysfunction in aorta and MRA; 4) the plasma and cardiovascular oxidative stress and the reduced aortic nitric oxide (NO) bioavailability; 5) the increased cardiac levels of the cytokines interleukin (IL)-1ß, IL-6, and C-C motif chemokine ligand 2 (Ccl2), the T cell marker cluster of differentiation 3 (Cd3), the inflammasome NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3), the proinflammatory enzymes inducible nitric oxide synthase (iNOS) and COX-2, the toll-like receptor 4 (TLR4) adapter protein myeloid differentiation primary response 88 (MyD88), and the nuclear factor kappa B (NF-κB) subunit p65; 6) the greater aortic expression of the cytokines tumor necrosis factor alpha (Tnf-α), Ccl2 and IL-6, Cd3, iNOS, MyD88, and NLRP3. Although ITH13001 increased nuclear Nrf2 levels and heme oxygenase 1 (HO-1) expression in vascular smooth muscle cells, both cardiac and vascular Nrf2, Ho-1, and NADPH quinone dehydrogenase 1 (Nqo1) levels remained unmodified irrespective of AngII infusion. Summarizing, ITH13001 improved hypertension-associated cardiovascular alterations independently of Nrf2 pathway activation, likely due to its direct antioxidant and anti-inflammatory properties. Therefore, ITH13001 could be a useful therapeutic strategy in patients with resistant hypertension. SIGNIFICANCE STATEMENT: Despite the existing therapeutic arsenal, only half of the patients treated for hypertension have adequately controlled blood pressure; therefore, the search for new compounds to control this pathology and the associated damage to end-target organs (cerebral, cardiac, vascular, renal) is of particular interest. The present study demonstrates that a new melatonin derivative, ITH13001, prevents hypertension development and the associated cardiovascular alterations due to its antioxidant and anti-inflammatory properties, making this compound a potential candidate for treatment of resistant hypertensive patients.

Chymase-independent vascular Ang-(1-12)/Ang II pathway and TXA2 generation are involved in endothelial dysfunction in the murine model of heart failure.

The angiotensin (Ang)-(1-12)/Ang II pathway contributes to cardiac pathology. However, its involvement in the development of peripheral endothelial dysfunction associated with heart failure (HF) remains unknown. Therefore, this study aimed to characterise the effect of exogenous Ang-(1-12) and its conversion to Ang II on endothelial function using the murine model of HF (Tgαq*44 mice), focusing on the role of chymase and vascular-derived thromboxane A2 (TXA2). Ex vivo myographic assessments of isolated aorta showed impaired endothelium-dependent vasodilation in late-stage HF in 12-month-old Tgαq*44 mice. However, endothelium-dependent vasodilation was fully preserved in the early stage of HF in 4-month-old Tgαq*44 mice and 4- and 12-month-old FVB control mice. Ang-(1-12) impaired endothelium-dependent vasodilation in 4- and 12-month-old Tgαq*44 mice, that was associated with increased Ang II production. The chymase inhibitor chymostatin did not inhibit this response. Interestingly, TXA2 production reflected by TXB2 measurement was upregulated in response to Ang-(1-12) and Ang II in aortic rings isolated from 12-month-old Tgαq*44 mice but not from 4-month-old Tgαq*44 mice or age-matched FVB mice. Furthermore, in vivo magnetic resonance imaging showed that Ang-(1-12) impaired endothelium-dependent vasodilation in the aorta of Tgαq*44 mice and FVB mice. However, this response was inhibited by angiotensin I converting enzyme (ACE) inhibitor; perindopril, angiotensin II receptor type 1 (AT1) antagonist; losartan and TXA2 receptor (TP) antagonist-picotamide in 12-month-old-Tgαq*44 mice only. In conclusion, the chymase-independent vascular Ang-(1-12)/Ang II pathway and subsequent TXA2 overactivity contribute to systemic endothelial dysfunction in the late stage of HF in Tgαq*44 mice. Therefore, the vascular TXA2 receptor represents a pharmacotherapeutic target to improve peripheral endothelial dysfunction in chronic HF.

Receptor mineralocorticoide extrarrenal. Una posible nueva diana para combatir el daño vascular / Extrarenal mineralocorticoid receptor. A potential new target against vascular damage

El receptor mineralocorticoide (MR) y su principal ligando la aldosterona juegan un papel fundamental en la regulación de la presión arterial a través de sus efectos facilitadores de la reabsorción de sodio y agua. Los antagonistas del receptor de la aldosterona son fármacos de probada eficacia, que en la actualidad se utilizan en pacientes seleccionados con hipertensión arterial resistente. Además, estos fármacos aumentan la supervivencia en diversas circunstancias como en la insuficiencia cardiaca, proporcionan protección renal en pacientes con enfermedad renal crónica y tienen efectos beneficiosos adicionales en otras patologías. Más allá de sus efectos cardiorrenales, en la actualidad sabemos que el MR se expresa en otros tejidos como células musculares lisas y endoteliales vasculares mediando efectos deletéreos tales como remodelado vascular, rigidez vascular y disfunción endotelial, los cuales son factores pronósticos de futuros eventos cardiovasculares. Además, nuevas evidencias experimentales demuestran que el MR se expresa también en células adyacentes a la vasculatura como células inmunes y adipocitos a través de los cuales podría influir en la función y estructura vascular. Entre los mecanismos responsables de dichos efectos se incluyen mecanismos genómicos y no genómicos, que facilitan la producción de especies reactivas de oxígeno de distintas fuentes, entre las que destaca la enzima NADPH oxidasa, así como de otros mediadores inflamatorios. En este artículo se revisan las evidencias experimentales y clínicas que sugieren que la activación del MR por aldosterona es un importante mediador de daño vascular a través de la producción de especies reactivas de oxígeno. (AU)

Mineralocorticoid receptor (MR) and its main ligand aldosterone, play a key role in the regulation of blood pressure through their effects increasing sodium and water reabsorption. MR antagonists are effective drugs that are currently used in selected patients with resistant hypertension. In addition, these drugs increase patients survival in specific circumstances such as heart failure, they offer renal protection in chronic kidney disease patients and they have beneficial effects in other pathologies. Besides MR cardiorenal effects, it is now accepted that MR is expressed in other tissues and cells such as vascular smooth muscle cells and endothelial cells where excessive MR activation induces deleterious effects such as vascular remodeling and stiffness and endothelial dysfunction, which are prognostic factors for future cardiovascular events. Moreover, novel evidence demonstrate that MR is also expressed in non-vascular cells adjacent to vessels such as immune cells and adipocytes that might influence vascular function and structure. Among the mechanisms responsible for these effects of MR are genomic and non genomic mechanisms that facilitate reactive oxygen species production mainly from the NADPH oxidase enzyme, as well as production of other inflammatory mediators. Here we review the experimental and clinical evidence that suggest that MR activation by aldosterone is an important mediator of vascular damage through the production of reactive oxygen species. (AU)

Receptor mineralocorticoide extrarrenal. Una posible nueva diana para combatir el daño vascular / Extrarenal mineralocorticoid receptor. A potential new target against vascular damage

El receptor mineralocorticoide (MR) y su principal ligando la aldosterona juegan un papel fundamental en la regulación de la presión arterial a través de sus efectos facilitadores de la reabsorción de sodio y agua. Los antagonistas del receptor de la aldosterona son fármacos de probada eficacia, que en la actualidad se utilizan en pacientes seleccionados con hipertensión arterial resistente. Además, estos fármacos aumentan la supervivencia en diversas circunstancias como en la insuficiencia cardiaca, proporcionan protección renal en pacientes con enfermedad renal crónica y tienen efectos beneficiosos adicionales en otras patologías. Más allá de sus efectos cardiorrenales, en la actualidad sabemos que el MR se expresa en otros tejidos como células musculares lisas y endoteliales vasculares mediando efectos deletéreos tales como remodelado vascular, rigidez vascular y disfunción endotelial, los cuales son factores pronósticos de futuros eventos cardiovasculares. Además, nuevas evidencias experimentales demuestran que el MR se expresa también en células adyacentes a la vasculatura como células inmunes y adipocitos a través de los cuales podría influir en la función y estructura vascular. Entre los mecanismos responsables de dichos efectos se incluyen mecanismos genómicos y no genómicos, que facilitan la producción de especies reactivas de oxígeno de distintas fuentes, entre las que destaca la enzima NADPH oxidasa, así como de otros mediadores inflamatorios. En este artículo se revisan las evidencias experimentales y clínicas que sugieren que la activación del MR por aldosterona es un importante mediador de daño vascular a través de la producción de especies reactivas de oxígeno

Mineralocorticoid receptor (MR) and its main ligand aldosterone, play a key role in the regulation of blood pressure through their effects increasing sodium and water reabsorption. MR antagonists are effective drugs that are currently used in selected patients with resistant hypertension. In addition, these drugs increase patients survival in specific circumstances such as heart failure, they offer renal protection in chronic kidney disease patients and they have beneficial effects in other pathologies. Besides MR cardiorenal effects, it is now accepted that MR is expressed in other tissues and cells such as vascular smooth muscle cells and endothelial cells where excessive MR activation induces deleterious effects such as vascular remodeling and stiffness and endothelial dysfunction, which are prognostic factors for future cardiovascular events. Moreover, novel evidence demonstrate that MR is also expressed in non-vascular cells adjacent to vessels such as immune cells and adipocytes that might influence vascular function and structure. Among the mechanisms responsible for these effects of MR are genomic and non genomic mechanisms that facilitate reactive oxygen species production mainly from the NADPH oxidase enzyme, as well as production of other inflammatory mediators. Here we review the experimental and clinical evidence that suggest that MR activation by aldosterone is an important mediator of vascular damage through the production of reactive oxygen species

La sobreexpresión vascular de la lisil oxidasa altera la estructura de la matriz extracelular e induce estrés oxidativo / Vascular lysyl oxidase over-expression alters extracellular matrix structure and induces oxidative stress

Introducción: La lisil oxidasa (LOX) contribuye al ensamblaje de las fibras de colágeno y elastina de la matriz extracelular (MEC). Hemos determinado las consecuencias de la sobreexpresión vascular de LOX sobre la estructura de la MEC y su contribución al estrés oxidativo. Métodos: Los estudios se desarrollaron en ratones que sobreexpresan la LOX (Tg) específicamente en células musculares lisas vasculares (CMLV). Se realizaron análisis por PCR a tiempo real, tinción de rojo sirio, producción de H2O2 y actividad NADPH oxidasa. Se caracterizaron las fenestras de la lámina elástica interna mediante microscopia confocal. Resultados: Las CMLV de ratones transgénicos presentaron niveles de actividad LOX superiores a los de animales control. En consonancia, las células transgénicas depositaron más fibras de elastina organizada y sus sobrenadantes indujeron un mayor ensamblaje de colágeno en ensayos in vitro. El nivel de colágeno maduro fue superior en la pared vascular de ratones Tg, que presentaban una menor área de las fenestras y un aumento de la expresión de la fibulina-5. La producción vascular de H2O2 y la actividad NADPH oxidasa fueron superiores en los ratones transgénicos. La incubación de CMLV con catalasa atenuó el incremento en la deposición de fibras de elastina madura inducido por la transgénesis de LOX. Conclusiones: La sobreexpresión de la LOX en CMLV se asocia a una alteración de la estructura vascular del colágeno y la elastina. La LOX podría constituir una nueva fuente de estrés oxidativo que participaría en la alteración estructural de la MEC y podría contribuir al remodelado vascular (AU)

Introduction: Lysyl oxidase (LOX) participates in the assembly of collagen and elastin fibres. The impact of vascular LOX over-expression on extracellular matrix (ECM) structure and its contribution to oxidative stress has been analysed. Methods: Studies were conducted on mice over-expressing LOX (Tg), specifically in smooth muscle cells (VSMC). Gene expression was assessed by real-time PCR analysis. Sirius Red staining, H2O2 production and NADPH oxidase activity were analysed in different vascular beds. The size and number of fenestra of the internal elastic lamina were determined by confocal microscopy. Results: LOX activity was up-regulated in VSMC of transgenic mice compared with cells from control animals. At the same time, transgenic cells deposited more organised elastin fibres and their supernatants induced a stronger collagen assembly in in vitro assays. Vascular collagen cross-linking was also higher in Tg mice, which showed a decrease in the size of fenestrae and an enhanced expression of Fibulin-5. Interestingly, higher H2O2 production and NADPH oxidase activity was detected in the vascular wall from transgenic mice. The H2O2 scavenger catalase attenuated the stronger deposition of mature elastin fibres induced by LOX transgenesis. Conclusions: LOX over-expression in VSMC was associated with a change in the structure of collagen and elastin fibres. LOX could constitute a novel source of oxidative stress that might participate in elastin changes and contribute to vascular remodeling (AU)