Targeting the ASMase/S1P pathway protects from sortilin-evoked vascular damage in hypertension.

Sortilin has been positively correlated with vascular disorders in humans. No study has yet evaluated the possible direct effect of sortilin on vascular function. We used pharmacological and genetic approaches coupled with study of murine and human samples to unravel the mechanisms recruited by sortilin in the vascular system. Sortilin induced endothelial dysfunction of mesenteric arteries through NADPH oxidase 2 (NOX2) isoform activation, dysfunction that was prevented by knockdown of acid sphingomyelinase (ASMase) or sphingosine kinase 1. In vivo, recombinant sortilin administration induced arterial hypertension in WT mice. In contrast, genetic deletion of sphingosine-1-phosphate receptor 3 (S1P3) and gp91phox/NOX2 resulted in preservation of endothelial function and blood pressure homeostasis after 14 days of systemic sortilin administration. Translating these research findings into the clinical setting, we detected elevated sortilin levels in hypertensive patients with endothelial dysfunction. Furthermore, in a population-based cohort of 270 subjects, we showed increased plasma ASMase activity and increased plasma levels of sortilin, S1P, and soluble NOX2-derived peptide (sNOX2-dp) in hypertensive subjects, and the increase was more pronounced in hypertensive subjects with uncontrolled blood pressure. Our studies reveal what we believe is a previously unrecognized role of sortilin in the impairment of vascular function and in blood pressure homeostasis and suggest the potential of sortilin and its mediators as biomarkers for the prediction of vascular dysfunction and high blood pressure.

Towards standardization of echocardiography for the evaluation of left ventricular function in adult rodents: a position paper of the ESC Working Group on Myocardial Function.

Echocardiography is a reliable and reproducible method to assess non-invasively cardiac function in clinical and experimental research. Significant progress in the development of echocardiographic equipment and transducers has led to the successful translation of this methodology from humans to rodents, allowing for the scoring of disease severity and progression, testing of new drugs, and monitoring cardiac function in genetically modified or pharmacologically treated animals. However, as yet, there is no standardization in the procedure to acquire echocardiographic measurements in small animals. This position paper focuses on the appropriate acquisition and analysis of echocardiographic parameters in adult mice and rats, and provides reference values, representative images, and videos for the accurate and reproducible quantification of left ventricular function in healthy and pathological conditions.

Role of Endothelial G Protein-Coupled Receptor Kinase 2 in Angioedema.

Excessive BK (bradykinin) stimulation is responsible for the exaggerated permeabilization of the endothelium in angioedema. However, the molecular mechanisms underlying these responses have not been investigated. BK receptors are Gq-protein-coupled receptors phosphorylated by GRK2 (G protein-coupled receptor kinase 2) with a hitherto unknown biological and pathophysiological significance. In the present study, we sought to identify the functional role of GRK2 in angioedema through the regulation of BK signaling. We found that the accumulation of cytosolic Ca2+ in endothelial cells induced by BK was sensitive to GRK2 activity, as it was significantly augmented by inhibiting the kinase. Accordingly, permeabilization and NO production induced by BK were enhanced, as well. In vivo, mice with reduced GRK2 levels in the endothelium (Tie2-CRE/GRK2fl+/fl-) exhibited an increased response to BK in terms of vascular permeability and extravasation. Finally, patients with reduced GRK2 levels displayed a severe phenotype of angioedema. Taken together, these findings establish GRK2 as a novel pivotal regulator of BK signaling with an essential role in the pathophysiology of vascular permeability and angioedema.

Pharmacological inhibition of GRK2 improves cardiac metabolism and function in experimental heart failure.

AIMS: The effects of GRK2 inhibition on myocardial metabolism in heart failure (HF) are unchartered. In this work, we evaluated the impact of pharmacological inhibition of GRK2 by a cyclic peptide, C7, on metabolic, biochemical, and functional phenotypes in experimental HF. METHODS AND RESULTS: C7 was initially tested on adult mice ventricular myocyte from wild type and GRK2 myocardial deficient mice (GRK2-cKO), to assess the selectivity on GRK2 inhibition. Then, chronic infusion of 2 mg/kg/day of C7 was performed in HF mice with cryogenic myocardial infarction. Cardiac function in vivo was assessed by echocardiography and cardiac catheterization. Histological, biochemical, and metabolic studies were performed on heart samples at time points. C7 induces a significant increase of contractility in wild type but not in adult ventricle myocytes from GRK2-cKO mice, thus confirming C7 selectivity for GRK2. In HF mice, 4 weeks of treatment with C7 improved metabolic features, including mitochondrial organization and function, and restored the biochemical and contractile responses. CONCLUSIONS: GRK2 is a critical molecule in the physiological regulation of cardiac metabolism. Its alterations in the failing heart can be pharmacologically targeted, leading to the correction of metabolic and functional abnormalities observed in HF.

New Nutraceutical Combination Reduces Blood Pressure and Improves Exercise Capacity in Hypertensive Patients Via a Nitric Oxide-Dependent Mechanism.

Background High blood pressure (BP) has long been recognized as a major health threat and, particularly, a major risk factor for stroke, cardiovascular disease, and end-organ damage. However, the identification of a novel, alternative, integrative approach for the control of BP and cardiovascular protection is still needed. Methods and Results Sixty-nine uncontrolled hypertension patients, aged 40 to 68 years, on antihypertensive medication were enrolled in 2 double-blind studies. Forty-five were randomized to placebo or a new nutraceutical combination named AkP05, and BP, endothelial function, and circulating nitric oxide were assessed before and at the end of 4 weeks of treatment. Twenty-four patients were randomized to diuretic or AkP05 for 4 weeks and underwent a cardiopulmonary exercise test to evaluate the effects of AkP05 on functional capacity of the cardiovascular, pulmonary, and muscular systems. Vascular and molecular studies were undertaken on mice to characterize the action of the single compounds contained in the AkP05 nutraceutical combination. AkP05 supplementation reduced BP, improved endothelial function, and increased nitric oxide release; cardiopulmonary exercise test revealed that AkP05 increased maximum O2 uptake, stress tolerance, and maximal power output. In mice, AkP05 reduced BP and improved endothelial function, evoking increased nitric oxide release through the PKCα/Akt/endothelial nitric oxide synthase pathway and reducing reactive oxygen species production via NADPH-oxidase inhibition. These effects were mediated by synergism of the single compounds of AkP05. Conclusions This is the first study reporting positive effects of a nutraceutical combination on the vasculature and exercise tolerance in treated hypertensive patients. Our findings suggest that AkP05 may be used as an adjunct for the improvement of cardiovascular protection and to better control BP in uncontrolled hypertension.

PERK-Mediated Unfolded Protein Response Activation and Oxidative Stress in PARK20 Fibroblasts.

PARK20, an early onset autosomal recessive parkinsonism is due to mutations in the phosphatidylinositol-phosphatase Synaptojanin 1 (Synj1). We have recently shown that the early endosomal compartments are profoundly altered in PARK20 fibroblasts as well as the endosomal trafficking. Here, we report that PARK20 fibroblasts also display a drastic alteration of the architecture and function of the early secretory compartments. Our results show that the exit machinery from the Endoplasmic Reticulum (ER) and the ER-to-Golgi trafficking are markedly compromised in patient cells. As a consequence, PARK20 fibroblasts accumulate large amounts of cargo proteins within the ER, leading to the induction of ER stress. Interestingly, this stressful state is coupled to the activation of the PERK/eIF2α/ATF4/CHOP pathway of the Unfolded Protein Response (UPR). In addition, PARK20 fibroblasts reveal upregulation of oxidative stress markers and total ROS production with concomitant alteration of the morphology of the mitochondrial network. Interestingly, treatment of PARK20 cells with GSK2606414 (GSK), a specific inhibitor of PERK activity, restores the level of ROS, signaling a direct correlation between ER stress and the induction of oxidative stress in the PARK20 cells. All together, these findings suggest that dysfunction of early secretory pathway might contribute to the pathogenesis of the disease.

The Main Determinants of Diabetes Mellitus Vascular Complications: Endothelial Dysfunction and Platelet Hyperaggregation.

Diabetes mellitus is a common disease that affects 3⁻5% of the general population in Italy. In some countries of northern Europe or in North America, it can even affect 6⁻8% of the population. Of great concern is that the number of cases of diabetes is constantly increasing, probably due to the increase in obesity and the sedentary nature of the population. According to the World Health Organization, in the year 2030 there will be 360 million people with diabetes, compared to 170 million in 2000. This has important repercussions on the lives of patients and their families, and on health systems that offer assistance to patients. In this review, we try to describe in an organized way the pathophysiological continuity between diabetes mellitus, endothelial dysfunction, and platelet hyperaggregation, highlighting the main molecular mechanisms involved and the interconnections.

The Impact of Aging on Cardio and Cerebrovascular Diseases.

A growing number of evidences report that aging represents the major risk factor for the development of cardio and cerebrovascular diseases. Understanding Aging from a genetic, biochemical and physiological point of view could be helpful to design a better medical approach and to elaborate the best therapeutic strategy to adopt, without neglecting all the risk factors associated with advanced age. Of course, the better way should always be understanding risk-to-benefit ratio, maintenance of independence and reduction of symptoms. Although improvements in treatment of cardiovascular diseases in the elderly population have increased the survival rate, several studies are needed to understand the best management option to improve therapeutic outcomes. The aim of this review is to give a 360° panorama on what goes on in the fragile ecosystem of elderly, why it happens and what we can do, right now, with the tools at our disposal to slow down aging, until new discoveries on aging, cardio and cerebrovascular diseases are at hand.

Correction: Akap1 Deficiency Promotes Mitochondrial Aberrations and Exacerbates Cardiac Injury Following Permanent Coronary Ligation via Enhanced Mitophagy and Apoptosis.

[This corrects the article DOI: 10.1371/journal.pone.0154076.].

Akap1 Deficiency Promotes Mitochondrial Aberrations and Exacerbates Cardiac Injury Following Permanent Coronary Ligation via Enhanced Mitophagy and Apoptosis.

A-kinase anchoring proteins (AKAPs) transmit signals cues from seven-transmembrane receptors to specific sub-cellular locations. Mitochondrial AKAPs encoded by the Akap1 gene have been shown to modulate mitochondrial function and reactive oxygen species (ROS) production in the heart. Under conditions of hypoxia, mitochondrial AKAP121 undergoes proteolytic degradation mediated, at least in part, by the E3 ubiquitin ligase Seven In-Absentia Homolog 2 (Siah2). In the present study we hypothesized that Akap1 might be crucial to preserve mitochondrial function and structure, and cardiac responses to myocardial ischemia. To test this, eight-week-old Akap1 knockout mice (Akap1-/-), Siah2 knockout mice (Siah2-/-) or their wild-type (wt) littermates underwent myocardial infarction (MI) by permanent left coronary artery ligation. Age and gender matched mice of either genotype underwent a left thoracotomy without coronary ligation and were used as controls (sham). Twenty-four hours after coronary ligation, Akap1-/- mice displayed larger infarct size compared to Siah2-/- or wt mice. One week after MI, cardiac function and survival were also significantly reduced in Akap1-/- mice, while cardiac fibrosis was significantly increased. Akap1 deletion was associated with remarkable mitochondrial structural abnormalities at electron microscopy, increased ROS production and reduced mitochondrial function after MI. These alterations were associated with enhanced cardiac mitophagy and apoptosis. Autophagy inhibition by 3-methyladenine significantly reduced apoptosis and ameliorated cardiac dysfunction following MI in Akap1-/- mice. These results demonstrate that Akap1 deficiency promotes cardiac mitochondrial aberrations and mitophagy, enhancing infarct size, pathological cardiac remodeling and mortality under ischemic conditions. Thus, mitochondrial AKAPs might represent important players in the development of post-ischemic cardiac remodeling and novel therapeutic targets.

Novel Molecular Approaches in Heart Failure: Seven Trans-Membrane Receptors Signaling in the Heart and Circulating Blood Leukocytes.

Heart failure (HF) is the result of molecular, cellular, and structural changes induced by cardiac load or injury. A complex network of signaling pathways have been involved in the development and progression of cardiac dysfunction. In this review, we summarize the pivotal role of seven trans-membrane receptors (7TMRs), also called G-protein-coupled receptors (GPCRs), in HF. Moreover, we will discuss the current knowledge on the potential mirroring of 7TMR signaling between circulating blood leukocytes and the heart, and the related future possibilities in the management of HF patients.

Dermcidin: a skeletal muscle myokine modulating cardiomyocyte survival and infarct size after coronary artery ligation.

AIMS: Coronary artery disease is the leading cause of death in western countries, and its association with lower extremity peripheral artery disease (LE-PAD) represents an independent predictor of worse outcome. However, the molecular mechanisms underlying these effects are currently unknown. METHODS AND RESULTS: To investigate these processes, we used in vitro approaches and several mouse models: (i) unilateral limb ischaemia by left common femoral artery ligation [peripheral ischaemia (PI), n = 38]; (ii) myocardial infarction by permanent ligation of the left descending coronary artery (MI, n = 40); (iii) MI after 5 weeks of limb ischaemia (PI + MI, n = 44); (iv) sham operation (SHAM, n = 20). Compared with MI, PI + MI hearts were characterized by a significant increase in cardiomyocyte apoptosis, larger infarct areas, and decreased cardiac function. By using a proteomic approach, we identified a ≅ 8 kDa circulating peptide, Dermcidin (DCD), secreted by ischaemic skeletal muscles, enhancing cardiomyocytes apoptosis under hypoxic conditions and infarct size after permanent coronary artery ligation. siRNA interference experiments to reduce DCD circulating levels significantly reduced infarct size and ameliorated cardiac function after MI. CONCLUSION: Our data demonstrate that chronic limb ischaemia activates detrimental pathways in the ischaemic heart through humoral mechanisms of remote organ crosstalk. Thus, DCD may represent a novel important myokine modulating cardiomyocyte survival and function.

[Novel pharmacological strategies for aortic dilation in Marfan syndrome: from mouse models to human patients]. / Nuove strategie farmacologiche per la sindrome di Marfan: dai modelli animali all'uomo.

Marfan syndrome (MS) is a congenital disorder of the connective tissue characterized by aortic dilation with frequent progression to aortic aneurysms requiring surgical intervention. Although mutations in the fibrillin-1 (FBN1) gene have been recognized as the genetic cause of MS a long time ago, only recently deeper knowledge of the molecular mechanisms underlying fibrillin-1 biology and the crucial role of transforming growth factor-ß and angiotensin II receptor type 1 antagonists have been elucidated. This review focuses on the most commonly used animal models to investigate the molecular mechanisms underlying MS, and on novel pharmacological strategies to reduce aortic dilation in MS.