Angiopoietin-like 2 (ANGPTL2) is a pro-inflammatory and pro-oxidant circulating protein that predicts and promotes chronic inflammatory diseases such as atherosclerosis in humans. Transgenic murine ...models demonstrated the deleterious role of ANGPTL2 in vascular diseases, while deletion of ANGPTL2 was protective. The nature of its role in cardiac tissues is, however, less clear. Indeed, in adult mice knocked down (KD) for ANGPTL2, we recently reported a mild left ventricular (LV) dysfunction originating from a congenital aortic valve stenosis, demonstrating that ANGPTL2 is essential to cardiac development and function.
Because we originally demonstrated that the KD of ANGPTL2 protected vascular endothelial function via an upregulation of arterial NOX4, promoting the beneficial production of dilatory H
O
, we tested the hypothesis that increased cardiac NOX4 could negatively affect cardiac redox and remodeling and contribute to LV dysfunction observed in adult
-KD mice.
Cardiac expression and activity of NOX4 were higher in KD mice, promoting higher levels of cardiac H
O
when compared to wild-type (WT) mice. Immunofluorescence showed that ANGPTL2 and NOX4 were co-expressed in cardiac cells from WT mice and both proteins co-immunoprecipitated in HEK293 cells, suggesting that ANGPTL2 and NOX4 physically interact. Pressure overload induced by transverse aortic constriction surgery (TAC) promoted LV systolic dysfunction in WT mice but did not further exacerbate the dysfunction in KD mice. Importantly, the severity of LV systolic dysfunction in KD mice (TAC and control SHAM) correlated with cardiac
expression. Injection of an adeno-associated virus (AAV9) delivering shRNA targeting cardiac
expression fully reversed LV systolic dysfunction in KD-SHAM mice, demonstrating the causal role of NOX4 in cardiac dysfunction in KD mice. Targeting cardiac
expression in KD mice also induced an antioxidant response characterized by increased expression of NRF2/KEAP1 and catalase.
Together, these data reveal that the absence of ANGPTL2 induces an upregulation of cardiac NOX4 that contributes to oxidative stress and LV dysfunction. By interacting and repressing cardiac NOX4, ANGPTL2 could play a new beneficial role in the maintenance of cardiac redox homeostasis and function.
The adenylate cyclase type 9 (ADCY9) gene appears to determine atherosclerotic outcomes in patients treated with dalcetrapib. In mice, we recently demonstrated that Adcy9 inactivation potentiates ...endothelial function and inhibits atherogenesis. The objective of this study was to characterize the contribution of ADCY9 to the regulation of endothelial signalling pathways involved in atherosclerosis.
We show that ADCY9 is expressed in the endothelium of mouse aorta and femoral arteries. We demonstrate that ADCY9 inactivation in cultured endothelial cells paradoxically increases cAMP accumulation in response to the adenylate cyclase activators forskolin and vasoactive intestinal peptide (VIP). Reciprocally, ADCY9 overexpression decreases cAMP production. Using mouse femoral artery arteriography, we show that Adcy9 inactivation potentiates VIP-induced endothelial-dependent vasodilation. Moreover, Adcy9 inactivation reduces mouse atheroma endothelial permeability in different vascular beds. ADCY9 overexpression reduces forskolin-induced phosphorylation of Ser157-vasodilator-stimulated phosphoprotein (VASP) and worsens thrombin-induced fall of RAP1 activity, both leading to increased endothelial permeability. ADCY9 inactivation in thrombin-stimulated human coronary artery endothelial cells results in cAMP accumulation, increases p-Ser157-VASP, and inhibits endothelial permeability. MLC2 phosphorylation and actin stress fibre increases in response to thrombin were reduced by ADCY9 inactivation, suggesting actin cytoskeleton regulation. Finally, using the Miles assay, we demonstrate that Adcy9 regulates thrombin-induced endothelial permeability in vivo in normal and atherosclerotic animals.
Adcy9 is expressed in endothelial cells and regulates local cAMP and endothelial functions including permeability relevant to atherogenesis.
Lean patients with NAFLD may develop cardiac complications independently of pre-existent metabolic disruptions and comorbidities. To address the underlying mechanisms independent of the development ...of obesity, we used a murine model of hepatic mitochondrial deficiency. The liver-heart axis was studied as these mice develop microvesicular steatosis without obesity. Our results unveil a sex-dependent phenotypic remodeling beyond liver damage. Males, more than females, show fasting hypoglycemia and increased insulin sensitivity. They exhibit diastolic dysfunction, remodeling of the circulating lipoproteins and cardiac lipidome. Conversely, females do not manifest cardiac dysfunction but exhibit cardiometabolic impairments supported by impaired mitochondrial integrity and β-oxidation, remodeling of circulating lipoproteins and intracardiac accumulation of deleterious triglycerides. This study underscores metabolic defects in the liver resulting in significant sex-dependent cardiac abnormalities independent of obesity. This experimental model may prove useful to better understand the sex-related variability, notably in the heart, involved in the progression of lean-NAFLD.
The influence of vegetation and microtopography on fine‐scale variability of thaw depth is largely unknown but potentially important for improving modeling of ecosystem–permafrost interactions. To ...elucidate their influence, we measured tree density, shrub cover and cryptogam presence (lichen and bryophyte) on forested permafrost peat plateaus in the discontinuous permafrost zone in the southern Northwest Territories, Canada. Greater tree density was associated with shallower thaw depth (approximately one quarter of the variance), whereas shrub cover had a negligible influence on thaw depth. Cryptogam species influenced thaw depth, with greater thaw depth associated with Sphagnum than with Cladonia (a difference on the order of 10%). Greater thaw depth occurred beneath hummocks than beneath hollows (a difference also on the order of 10%). Together, canopy cover, cryptogam species and microforms contribute to a variation of roughly half the variance in thaw depth in the peat plateau landscape.
Recent development in the field of COPD has focused on strategies aimed at reducing the underlying inflammation through selective inhibition of the phosphodiesterase type IV (PDE4) isoform. Although ...the anti-inflammatory and bronchodilator activity of selective PDE4 inhibitors has been well documented, their low therapeutic ratio and dose-dependent systemic side effects have limited their clinical utility. This study examined the effect of 2'-deoxy-2'-Fluoro-beta-D-Arabinonucleic Acid (FANA)-containing antisense oligonucleotides (AON) targeting the mRNA for the PDE4B/4D and 7A subtypes on lung inflammatory markers, both in vitro and in vivo.
Normal human bronchial epithelial (NHBE) cells were transfected with FANA AON against PDE4B/4D and 7A alone or in combination. mRNA levels for target PDE subtypes, as well as secretion of pro-inflammatory chemokines were then measured following cell stimulation. Mice were treated with combined PDE4B/4D and 7A AON via endo-tracheal delivery, or with roflumilast via oral delivery, and exposed to cigarette smoke for one week. Target mRNA inhibition, as well as influx of inflammatory cells and mediators were measured in lung lavages. A two-week smoke exposure protocol was also used to test the longer term potency of PDE4B/4D and 7A AONs.
In NHBE cells, PDE4B/4D and 7A AONs dose-dependently and specifically inhibited expression of their respective target mRNA. When used in combination, PDE4B/4D and 7A AONs significantly abrogated the cytokine-induced secretion of IL-8 and MCP-1 to near baseline levels. In mice treated with combined PDE4B/4D and 7A AONs and exposed to cigarette smoke, significant protection against the smoke-induced recruitment of neutrophils and production of KC and pro-MMP-9 was obtained, which was correlated with inhibition of target mRNA in cells from lung lavages. In this model, PDE AONs exerted more potent and broader anti-inflammatory effects against smoke-induced lung inflammation than roflumilast. Moreover, the protective effect of PDE4B/4D and 7A AON was maintained when a once-weekly treatment schedule was used.
These results indicate that inhaled AON against PDE4B/4D and 7A have unique effects on biomarkers that are believed to be important in the pathophysiology of COPD, which supports further development as a potential therapy in this disease.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
BACKGROUND:Pharmacogenomic studies have shown that ADCY9 genotype determines the effects of the CETP (cholesteryl ester transfer protein) inhibitor dalcetrapib on cardiovascular events and ...atherosclerosis imaging. The underlying mechanisms responsible for the interactions between ADCY9 and CETP activity have not yet been determined.
METHODS:Adcy9-inactivated (Adcy9) and wild-type (WT) mice, that were or not transgenic for the CETP gene (CETPtgAdcy9 and CETPtgAdcy9), were submitted to an atherogenic protocol (injection of an AAV8 adeno-associated virus serotype 8 expressing a PCSK9 proprotein convertase subtilisin/kexin type 9 gain-of-function variant and 0.75% cholesterol diet for 16 weeks). Atherosclerosis, vasorelaxation, telemetry, and adipose tissue magnetic resonance imaging were evaluated.
RESULTS:Adcy9 mice had a 65% reduction in aortic atherosclerosis compared to WT (P<0.01). CD68 (cluster of differentiation 68)-positive macrophage accumulation and proliferation in plaques were reduced in Adcy9 mice compared to WT animals (P<0.05 for both). Femoral artery endothelial-dependent vasorelaxation was improved in Adcy9 mice (versus WT, P<0.01). Selective pharmacological blockade showed that the nitric oxide, cyclooxygenase, and endothelial-dependent hyperpolarization pathways were all responsible for the improvement of vasodilatation in Adcy9 (P<0.01 for all). Aortic endothelium from Adcy9 mice allowed significantly less adhesion of splenocytes compared to WT (P<0.05). Adcy9 mice gained more weight than WT with the atherogenic diet; this was associated with an increase in whole body adipose tissue volume (P<0.01 for both). Feed efficiency was increased in Adcy9 compared to WT mice (P<0.01), which was accompanied by prolonged cardiac RR interval (P<0.05) and improved nocturnal heart rate variability (P=0.0572). Adcy9 inactivation–induced effects on atherosclerosis, endothelial function, weight gain, adipose tissue volume, and feed efficiency were lost in CETPtgAdcy9 mice (P>0.05 versus CETPtgAdcy9).
CONCLUSIONS:Adcy9 inactivation protects against atherosclerosis, but only in the absence of CETP activity. This atheroprotection may be explained by decreased macrophage accumulation and proliferation in the arterial wall, and improved endothelial function and autonomic tone.
Introduction: Up to 50% of community-dwelling older adults report living with some chronic pain that interferes with their daily functioning and leads to disabilities. Hence, it is crucial to provide ...these individuals with strategies to effectively manage pain. An interdisciplinary approach is warranted considering the numerous factors contributing to pain among older adults. Although several studies have been conducted on various interdisciplinary pain self-management programs, little effort has been made to synthesize knowledge about such programs for older adults. Objective: The objective of this review was to synthesize the characteristics and effects of interdisciplinary chronic pain self-management interventions targeting community-dwelling older adults. Methods: A scoping review was conducted following the steps recommended by Arksey and O’Malley (2005) and Levac et al. (2010). Keyword searches were performed in MEDLINE, CINAHL, EMBASE, and the Cochrane Library. Results: Sixty-six articles were included. Most interventions were based on a cognitive-behavioral group approach and used a combination of modalities, including education and training on the use of self-management strategies. The professionals most frequently involved in group interventions were psychologists, physiotherapists, and occupational therapists. Several benefits of these programs have been reported concerning pain intensity, independence in daily functioning, mental health, and quality of life. Conclusions: Interdisciplinary chronic pain self-management programs appear promising in guiding clinical and rehabilitation interventions for older adults living with chronic pain.
Introduction
Heart failure (HF) is still a major cause of mortality worldwide. HF pathogenesis involves disturbances in cardiac energy metabolism. Studies have shown that preventive treatment with a ...diet supplemented with vitamins B3 or B9/B12 in experimental models of HF, exhibits beneficial effects on cardiac and mitochondrial functions and improves survival. Therefore, the overall objective of our pilot study is to evaluate the curative benefit of a synthetic diet enriched with vitamins B3 (nicotinamide riboside), B9 and B12 (BVit) in a mouse model of HF based on the hypothesis that this enriched diet is beneficial for cardiac function via an improvement of cardiac metabolism.
Method
Pressure overload was induced by transverse aortic constriction (TAC) in 8‐week‐old male and female C57Bl6/N mice. Four weeks post‐TAC and according to their cardiac function evaluated by echocardiography, mice were randomised to a BVit‐enriched diet or not and compared to SHAM animals. The criteria of selection for randomisation were as follows: 10% decrease in ejection fraction (EF), 30% increase in left ventricular (LV) mass and an average pressure gradient of 60mmHg. Mice survival was evaluated and cardiac function was assessed by echocardiography every 4 weeks. Blood samples were taken at 8 weeks of treatment in fasted mice (5 hours) for non‐targeted lipidomics mass spectrometry‐based analysis.
Results
Our pilot study show that survival is not improved in males while mortality is reduced in females from 12 weeks of treatment. In males, the reduced EF in the TAC group is not improved by BVit treatment and myocardial hypertrophy, as illustrated by the left ventricular mass (+20% in TAC), is exacerbated with BVit treatment. In contrast, in females, both EF and cardiac hypertrophy were improved (+20% and ‐13% respectively) after 12 weeks of BVit treatment. To better understand the sexual dimorphism in the response of BVit, non‐targeted lipidomics was used on plasma from mice following 8 weeks of treatment. In TAC‐females, compared to their SHAM controls, a decrease in triglycerides (TG) and an increase in choline phospholipids were observed while the lipid profile was normalized with BVit treatment. In TAC‐males vs SHAM, however, TGs were significantly increased and the treatment with BVit exacerbated the lipidomic profile both in terms of TGs and additional lipid species (identification in progress).
Conclusion
Our pilot study suggests a sexual dimorphism in the response to BVit treatment in experimental HF. Indeed, the benefit of BVit treatment is only shown in females with a delay in the mortality rate associated with improved cardiac function and normalisation of lipid disturbances. To explore and understand the mechanisms underlying this sexual dimorphism, the lipid profile hypothesis appears as a relevant avenue to explore in the future.
Objective
In non‐alcoholic fatty liver disease (NAFLD), liver mitochondrial dysfunction plays an important role in the development of cardiac abnormalities independent of obesity per se. However, the ...mechanisms underlying the development of these abnormalities, and whether these are affected by sex remain unclear. In the present study, we sought to address this question using a mouse model of hepatic mitochondrial deficiency caused by loss of Lrpprc (H‐Lrpprc‐/‐) as these mice develop microvesicular steatosis and a NAFLD lipidomic‐like profile without obesity.
Hypothesis
Our working hypothesis is that metabolic defects in the liver would trigger metabolic and functional abnormalities in the heart in a sex‐dependent manner.
Methods
Detailed phenotyping experiments were performed in male and female H‐Lrpprc‐/‐mice and their controls at 14 weeks of age. Glucose metabolism was monitored by blood glucose as well as insulin, and glucose tolerance tests (ITT, OGTT). Cardiac manifestations were studied using molecular (qPCR), lipidomic (mass spectrometry) and functional (oximetry on isolated mitochondria, intraventricular pressures by Millar probe) analyses.
Results
Genetic inactivation of Lrpprc resulted in an >60% reduction of LRPPRC protein content in both males and females, which resulted in comparable structural liver abnormalities. In contrast, the resulting metabolic and cardiac functional changes displayed a marked sexual dimorphism. Lrpprc deficiency in the liver was associated with fasting hypoglycemia and increased insulin sensitivity in both sexes, but more so in males. Lrpprc deficiency was also associated with a remodeling of specific markers of mitochondrial function exclusively in the female myocardium. This included 1) reduced expression of gene markers for mitochondrial biogenesis (Tfam), fusion (Mfn1‐2), and fatty acid (FA) utilization and oxidation (Pparα, Cd36, Cpt1b, Cpt2, Vlcad, Lcad, Mcad), 2) impairment of FA‐dependent mitochondrial respiration, and 3) increased cardiac triglyceride levels. Paradoxically, cardiac function was preserved in females, while males displayed mild diastolic dysfunction as evidenced by increased early and late diastolic pressures (0.29 and 2.39 fold vs. male wild type respectively) amongst other parameters.
Conclusion
Collectively, these results indicate that metabolic defects in the liver can result in significant sex‐dependent abnormalities that affect both the mitochondrial/metabolic phenotype and contractile function independent of obesity. This experimental model may prove useful to better understand the mechanisms underlying the sex‐related variability in the progression of lean NAFLD in humans.
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