Publications by authors named "Guido R Y De Meyer"

142 Publications

Altered stress hormone levels affect in vivo vascular function in the hAPP23 overexpressing mouse model of Alzheimer's disease.

Am J Physiol Heart Circ Physiol 2021 09 10. Epub 2021 Sep 10.

Lab of Physiopharmacology, University of Antwerp, Antwerp, Belgium.

Alzheimer's disease (AD) has long been considered a brain-specific dementia syndrome. However, in recent decades the occurrence of cardiovascular (CV) disease in the progression of AD has been confirmed by increasing epidemiological evidence. In this study, we conducted an in-depth cardiovascular characterization of a humanized APP overexpressing mouse model (hAPP23), which overexpresses the Swedish mutation (KM670/671NL). At the age of 6 months, hAPP23 mice had a lower survival, lower body weight and increased corticosterone and VMA levels compared to C57BL/6 littermates. Systolic blood pressure was increased in hAPP23 animals compared to C57BL/6 littermates, but diastolic blood pressure was not statistically different. Pulse pressure remained unchanged but abdominal and carotid pulse wave velocity (aPWV and cPWV) were increased in hAPP23 compared to C57BL/6 mice. Echocardiography showed no differences in systolic or diastolic cardiac function. Ex vivo evaluation of vascular function showed decreased adreno-receptor dependent vasoconstriction of hAPP23 aortic segments, although the isobaric biomechanics of the aortic wall were similar to C57BL/6 aortic segments. In conclusion, hAPP23 mice exhibited high serum corticosterone levels, elevated systolic blood pressure and increased arterial stiffness in vivo. However, ex vivo aortic stiffness of hAPP23 aortic segments was not changed and vascular reactivity to α-adrenoceptor stimulation was attenuated. These findings highlight the need for more frequent assessment of circulating stress hormone levels and PWV measurements in daily clinical practice for people at risk of AD.
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http://dx.doi.org/10.1152/ajpheart.00254.2021DOI Listing
September 2021

PFKFB3 gene deletion in endothelial cells inhibits intraplaque angiogenesis and lesion formation in a murine model of venous bypass grafting.

Angiogenesis 2021 Aug 25. Epub 2021 Aug 25.

Laboratory of Physiopharmacology, University of Antwerp, Universiteitsplein 1, B-2610, Antwerp, Belgium.

Vein grafting is a frequently used surgical intervention for cardiac revascularization. However, vein grafts display regions with intraplaque (IP) angiogenesis, which promotes atherogenesis and formation of unstable plaques. Graft neovessels are mainly composed of endothelial cells (ECs) that largely depend on glycolysis for migration and proliferation. In the present study, we aimed to investigate whether loss of the glycolytic flux enzyme phosphofructokinase-2/fructose-2,6-bisphosphatase 3 (PFKFB3) in ECs inhibits IP angiogenesis and as such prevents unstable plaque formation. To this end, apolipoprotein E deficient (ApoE) mice were backcrossed to a previously generated PFKFB3 Cdh5 mouse strain. Animals were injected with either corn oil (ApoEPFKFB3) or tamoxifen (ApoEPFKFB3), and were fed a western-type diet for 4 weeks prior to vein grafting. Hereafter, mice received a western diet for an additional 28 days and were then sacrificed for graft assessment. Size and thickness of vein graft lesions decreased by 35 and 32%, respectively, in ApoEPFKFB3 mice compared to controls, while stenosis diminished by 23%. Moreover, vein graft lesions in ApoEPFKFB3 mice showed a significant reduction in macrophage infiltration (29%), number of neovessels (62%), and hemorrhages (86%). EC-specific PFKFB3 deletion did not show obvious adverse effects or changes in general metabolism. Interestingly, RT-PCR showed an increased M2 macrophage signature in vein grafts from ApoEPFKFB3 mice. Altogether, EC-specific PFKFB3 gene deletion leads to a significant reduction in lesion size, IP angiogenesis, and hemorrhagic complications in vein grafts. This study demonstrates that inhibition of endothelial glycolysis is a promising therapeutic strategy to slow down plaque progression.
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http://dx.doi.org/10.1007/s10456-021-09816-3DOI Listing
August 2021

Serum Corticosterone and Insulin Resistance as Early Biomarkers in the hAPP23 Overexpressing Mouse Model of Alzheimer's Disease.

Int J Mol Sci 2021 Jun 22;22(13). Epub 2021 Jun 22.

Laboratory of Physiopharmacology, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Campus Drie Eiken, Universiteitsplein 1, University of Antwerp, 2610 Wilrijk, Antwerp, Belgium.

Increasing epidemiological evidence highlights the association between systemic insulin resistance and Alzheimer's disease (AD). As insulin resistance can be caused by high-stress hormone levels and since hypercortisolism appears to be an important risk factor of AD, we aimed to investigate the systemic insulin functionality and circulating stress hormone levels in a mutant humanized amyloid precursor protein (APP) overexpressing (hAPP23+/-) AD mouse model. Memory and spatial learning of male hAPP23+/- and C57BL/6 (wild type, WT) mice were assessed by a Morris Water Maze (MWM) test at the age of 4 and 12 months. The systemic metabolism was examined by intraperitoneal glucose and insulin tolerance tests (GTT, ITT). Insulin and corticosterone levels were determined in serum. In the hippocampus, parietal and occipital cortex of hAPP23+/- brains, amyloid-beta (Aβ) deposits were present at 12 months of age. MWM demonstrated a cognitive decline in hAPP23+/- mice at 12 but not at 4 months, evidenced by increasing total path lengths and deteriorating probe trials compared to WT mice. hAPP23+/- animals presented increased serum corticosterone levels compared to WT mice at both 4 and 12 months. hAPP23+/- mice exhibited peripheral insulin resistance compared to WT mice at 4 months, which stabilized at 12 months of age. Serum insulin levels were similar between genotypes at 4 months of age but were significantly higher in hAPP23+/- mice at 12 months of age. Peripheral glucose homeostasis remained unchanged. These results indicate that peripheral insulin resistance combined with elevated circulating stress hormone levels could be potential biomarkers of the pre-symptomatic phase of AD.
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http://dx.doi.org/10.3390/ijms22136656DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8269119PMC
June 2021

The PFKFB3 Inhibitor AZ67 Inhibits Angiogenesis Independently of Glycolysis Inhibition.

Int J Mol Sci 2021 May 31;22(11). Epub 2021 May 31.

Laboratory of Physiopharmacology, University of Antwerp, 2610 Antwerp, Belgium.

Angiogenesis is the process of new blood vessel formation. In this complex orchestrated growth, many factors are included. Lately, focus has shifted to endothelial cell metabolism, particularly to the PFKFB3 protein, a key regulatory enzyme of the glycolytic pathway. A variety of inhibitors of this important target have been studied, and a plethora of biological effects related to the process of angiogenesis have been reported. However, recent studies have disputed their mechanism of action, questioning whether all the effects are indeed due to PFKFB3 inhibition. Remarkably, the most well-studied inhibitor, 3PO, does not bind to PFKFB3, raising questions about this target. In our study, we aimed to elucidate the effects of PFKFB3 inhibition in angiogenesis by using the small molecule AZ67. We used isothermal titration calorimetry and confirmed binding to PFKFB3. In vitro, AZ67 did not decrease lactate production in endothelial cells (ECs), nor ATP levels, but exhibited good inhibitory efficacy in the tube-formation assay. Surprisingly, this was independent of EC migratory and proliferative abilities, as this was not diminished upon treatment. Strikingly however, even the lowest dose of AZ67 demonstrated significant inhibition of angiogenesis in vivo. To our knowledge, this is the first study to demonstrate that the process of angiogenesis can be disrupted by targeting PFKFB3 independently of glycolysis inhibition.
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http://dx.doi.org/10.3390/ijms22115970DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8198190PMC
May 2021

Neuregulin-1 compensates for endothelial nitric oxide synthase deficiency.

Am J Physiol Heart Circ Physiol 2021 06 14;320(6):H2416-H2428. Epub 2021 May 14.

Laboratory of Physiopharmacology, University of Antwerp, Antwerp, Belgium.

Endothelial cells (ECs) secrete different paracrine signals that modulate the function of adjacent cells; two examples of these paracrine signals are nitric oxide (NO) and neuregulin-1 (NRG1), a cardioprotective growth factor. Currently, it is undetermined whether one paracrine factor can compensate for the loss of another. Herein, we hypothesized that NRG1 can compensate for endothelial NO synthase (eNOS) deficiency. We characterized eNOS null and wild-type (WT) mice by cardiac ultrasound and histology and we determined circulating NRG1 levels. In a separate experiment, eight groups of mice were divided into four groups of eNOS null mice and WT mice; half of the mice received angiotensin II (ANG II) to induce a more severe phenotype. Mice were randomized to daily injections with NRG1 or vehicle for 28 days. eNOS deficiency increased NRG1 plasma levels, indicating that ECs increase their NRG1 expression when NO production is deleted. eNOS deficiency also increased blood pressure, lowered heart rate, induced cardiac fibrosis, and affected diastolic function. In eNOS null mice, ANG II administration not only increased cardiac fibrosis but also induced cardiac hypertrophy and renal fibrosis. NRG1 administration prevented cardiac and renal hypertrophy and fibrosis caused by ANG II infusion and eNOS deficiency. Moreover, expression in the myocardium is shown to be regulated by miR-134. This study indicates that administration of endothelium-derived NRG1 can compensate for eNOS deficiency in the heart and kidneys. ECs compensate for eNOS deficiency by increasing the secretion of NRG1. NRG1 administration prevents cardiac and renal hypertrophy and fibrosis caused by ANG II infusion and eNOS deficiency. NRG1 expression is regulated by miR-134.
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http://dx.doi.org/10.1152/ajpheart.00914.2020DOI Listing
June 2021

A systematic literature review on the effects of exercise on human Toll-like receptor expression.

Exerc Immunol Rev 2021 ;27:84-124

Laboratory of Physiopharmacology, GENCOR, University of Antwerp, Belgium.

Background: Toll-like receptors (TLRs) are a family of transmembrane pattern recognition receptors that are mainly expressed on immune cells. Recognition of various exogenous and endogenous molecular patterns activates the TLR signalling cascade, which orchestrates an inflammatory immune response. Dysfunctional immune responses, including aberrant TLR signalling, are increasingly implicated in the associations between sedentarism, chronic low-grade systemic inflammation and various non-communicable diseases. Conversely, exercise exerts anti-inflammatory effects, which could be conferred through its immunomodulatory properties, potentially affecting TLRs. This study aims to systematically review the effects of exercise on human TLR expression.

Method: A systematic literature search of Pubmed, Embase, The Cochrane Library and SPORTDiscus for articles addressing the impact of exercise (as isolated intervention) on TLRs in humans was conducted, ending in February 2020.

Results: A total of 66 articles were included. The publications were categorised according to exercise modality and duration: acute resistance exercise (4 studies), acute aerobic exercise (26 studies), resistance training program (9 studies), aerobic training program (16 studies), combined (i.e. resistance and aerobic) training program (8 studies) and chronic exercise not otherwise classifiable (9 studies). Five articles investigated more than one of the aforementioned exercise categories. Several trends could be discerned with regard to the TLR response in the different exercise categories. Acute resistance exercise seemed to elicit TLR upregulation, whereas acute aerobic exercise had less activating potential with the majority of responses being neutral or, especially in healthy participants, downregulatory. Chronic resistance and combined exercise programs predominantly resulted in unaltered or decreased TLR levels. In the chronic aerobic exercise category, mixed effects were observed, but the majority of measurements demonstrated unchanged TLR expression.

Conclusion: Currently published research supports an interplay between exercise and TLR signalling, which seems to depend on the characteristics of the exercise. However, there was large heterogeneity in the study designs and methodologies. Therefore, additional research is required to further corroborate these findings, to define its pathophysiological implications and to elucidate the mechanism(s) linking exercise to TLR signalling.
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May 2021

Doxorubicin induces arterial stiffness: A comprehensive in vivo and ex vivo evaluation of vascular toxicity in mice.

Toxicol Lett 2021 Aug 22;346:23-33. Epub 2021 Apr 22.

University of Antwerp, Faculty of Medicine and Health Sciences, Laboratory of Physiopharmacology, Campus Drie Eiken, Universiteitsplein 1, B-2610, Antwerp, Belgium.

Arterial stiffness is an important predictor of cardiovascular risk. Clinical studies have demonstrated that arterial stiffness increases in cancer patients treated with the chemotherapeutic doxorubicin (DOX). However, the mechanisms of DOX-induced arterial stiffness remain largely unknown. This study aimed to evaluate artery stiffening in DOX-treated mice using in vivo and ex vivo techniques. Male C57BL/6J mice were treated for 2 weeks with 2 mg/kg (low dose) or 4 mg/kg (high dose) of DOX weekly. Arterial stiffness was assessed in vivo with ultrasound imaging (abdominal aorta pulse wave velocity (aaPWV)) and applanation tonometry (carotid-femoral PWV) combined with ex vivo vascular stiffness and reactivity evaluation. The high dose increased aaPWV, while cfPWV did not reach statistical significance. Phenylephrine (PE)-contracted aortic segments showed a higher Peterson's modulus (Ep) in the high dose group, while Ep did not differ when vascular smooth muscle cells (VSMCs) were relaxed by a NO donor (DEANO). In addition, aortic rings of DOX-treated mice showed increased PE contraction, decreased basal nitric oxide (NO) index and impaired acetylcholine-induced endothelium-dependent relaxation. DOX treatment contributed to endothelial cell loss and reduced endothelial nitric oxide synthase (eNOS) expression in the aorta. In conclusion, we have replicated DOX-induced arterial stiffness in a murine model and this aortic stiffness is driven by impaired endothelial function, contributing to increased vascular tone.
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http://dx.doi.org/10.1016/j.toxlet.2021.04.015DOI Listing
August 2021

Inflammation, Nitro-Oxidative Stress, Impaired Autophagy, and Insulin Resistance as a Mechanistic Convergence Between Arterial Stiffness and Alzheimer's Disease.

Front Mol Biosci 2021 29;8:651215. Epub 2021 Mar 29.

Laboratory of Physiopharmacology, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Antwerp, Belgium.

The average age of the world's elderly population is steadily increasing. This unprecedented rise in the aged world population will increase the prevalence of age-related disorders such as cardiovascular disease (CVD) and neurodegeneration. In recent years, there has been an increased interest in the potential interplay between CVDs and neurodegenerative syndromes, as several vascular risk factors have been associated with Alzheimer's disease (AD). Along these lines, arterial stiffness is an independent risk factor for both CVD and AD. In this review, we discuss several inflammaging-related disease mechanisms including acute tissue-specific inflammation, nitro-oxidative stress, impaired autophagy, and insulin resistance which may contribute to the proposed synergism between arterial stiffness and AD.
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http://dx.doi.org/10.3389/fmolb.2021.651215DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8039307PMC
March 2021

Impact of myeloid RIPK1 gene deletion on atherogenesis in ApoE-deficient mice.

Atherosclerosis 2021 04 24;322:51-60. Epub 2021 Feb 24.

Laboratory of Physiopharmacology, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, B-2610, Antwerp, Belgium. Electronic address:

Background And Aims: Targeting macrophage death is a promising strategy for stabilizing atherosclerotic plaques. Recently, necroptosis was identified as a form of regulated necrosis in atherosclerosis. Receptor-interacting serine/threonine-protein kinase (RIPK)1 is an upstream regulator of RIPK3, which is a crucial kinase for necroptosis induction. We aimed to investigate the impact of myeloid-specific RIPK1 gene deletion on atherogenesis.

Methods: RIPK1LysM-CreApoE and RIPK1LysM-CreApoE mice were fed a western-type diet (WD) for 16 or 24 weeks to induce plaque formation.

Results: After 16 weeks WD, plaque area and percentage necrosis in RIPK1LysM-CreApoE mice were significantly decreased as compared to plaques of RIPK1LysM-CreApoE mice. Moreover, plaques of RIPK1LysM-CreApoE mice showed more apoptosis and a decreased macrophage content. After 24 weeks WD, plaque size and percentage necrosis were no longer different between the two groups. Free apoptotic cells strongly accumulated in plaques of RIPK1LysM-CreApoE mice. In addition to apoptosis, necroptosis was upregulated in plaques of RIPK1LysM-CreApoE mice. In vitro, TNF-α triggered apoptosis in RIPK1LysM-CreApoE, but not in RIPK1LysM-CreApoE macrophages. Moreover, RIPK1LysM-CreApoE macrophages were not protected against RIPK3-dependent necroptosis.

Conclusions: The impact of myeloid RIPK1 gene deletion depends on the stage of atherogenesis. At 16 weeks WD, myeloid RIPK1 gene deletion resulted in increased apoptosis, thereby slowing down plaque progression. However, despite decreased macrophage content, plaque and necrotic core size were no longer reduced after 24 weeks of WD, most likely due to the accumulation of free apoptotic and necroptotic cells.
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http://dx.doi.org/10.1016/j.atherosclerosis.2021.02.021DOI Listing
April 2021

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition).

Autophagy 2021 Jan 8;17(1):1-382. Epub 2021 Feb 8.

University of Crete, School of Medicine, Laboratory of Clinical Microbiology and Microbial Pathogenesis, Voutes, Heraklion, Crete, Greece; Foundation for Research and Technology, Institute of Molecular Biology and Biotechnology (IMBB), Heraklion, Crete, Greece.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field.
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http://dx.doi.org/10.1080/15548627.2020.1797280DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7996087PMC
January 2021

The Protective Effects of the Autophagic and Lysosomal Machinery in Vascular and Valvular Calcification: A Systematic Review.

Int J Mol Sci 2020 Nov 25;21(23). Epub 2020 Nov 25.

Laboratory of Physiopharmacology, University of Antwerp, 2610 Antwerp, Belgium.

Background: Autophagy is a highly conserved catabolic homeostatic process, crucial for cell survival. It has been shown that autophagy can modulate different cardiovascular pathologies, including vascular calcification (VCN).

Objective: To assess how modulation of autophagy, either through induction or inhibition, affects vascular and valvular calcification and to determine the therapeutic applicability of inducing autophagy.

Data Sources: A systematic review of English language articles using MEDLINE/PubMed, Web of Science (WoS) and the Cochrane library. The search terms included autophagy, autolysosome, mitophagy, endoplasmic reticulum (ER)-phagy, lysosomal, calcification and calcinosis. Study characteristics: Thirty-seven articles were selected based on pre-defined eligibility criteria. Thirty-three studies (89%) studied vascular smooth muscle cell (VSMC) calcification of which 27 (82%) studies investigated autophagy and six (18%) studies lysosomal function in VCN. Four studies (11%) studied aortic valve calcification (AVCN). Thirty-four studies were published in the time period 2015-2020 (92%).

Conclusion: There is compelling evidence that both autophagy and lysosomal function are critical regulators of VCN, which opens new perspectives for treatment strategies. However, there are still challenges to overcome, such as the development of more selective pharmacological agents and standardization of methods to measure autophagic flux.
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http://dx.doi.org/10.3390/ijms21238933DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7728070PMC
November 2020

Defective Autophagy in Vascular Smooth Muscle Cells Alters Vascular Reactivity of the Mouse Femoral Artery.

Front Physiol 2020 23;11:548943. Epub 2020 Sep 23.

Laboratory of Physiopharmacology, Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium.

Autophagy is an important cellular survival process that enables degradation and recycling of defective organelles and proteins to maintain cellular homeostasis. Hence, defective autophagy plays a role in many age-associated diseases, such as atherosclerosis, arterial stiffening and hypertension. Recently, we showed in mice that autophagy in vascular smooth muscle cells (VSMCs) of large elastic arteries such as the aorta is important for Ca mobilization and vascular reactivity. Whether autophagy plays a role in the smaller muscular arteries, such as the femoral artery, and thereby contributes to for example, blood pressure regulation is currently unknown. Therefore, we determined vascular reactivity of femoral artery segments of mice containing a VSMC specific deletion of the essential autophagy gene Atg7 (Atg7 SM22α-Cre) and compared them to femoral artery segments of corresponding control mice (Atg7 SM22α-Cre). Our results indicate that similar to the aorta, femoral artery segments showed enhanced contractility. Specifically, femoral artery segments of Atg7 SM22α-Cre mice showed an increase in phasic phenylephrine (PE) induced contractions, together with an enhanced sensitivity to depolarization induced contractions. In addition, and importantly, VSMC sensitivity to exogenous nitric oxide (NO) was significantly increased in femoral artery segments of Atg7 SM22α-Cre mice. Notwithstanding the fact that small artery contractility is a significant pathophysiological determinant for the development of hypertension, 7 days of treatment with angiotensin II (AngII), which increased systolic blood pressure in control mice, was ineffective in Atg7 SM22α-Cre mice. It is likely that this was due to the increased sensitivity of VSMCs to NO in the femoral artery, although changes in the heart upon AngII treatment were also present, which could also be (partially) accountable for the lack of an AngII-induced rise in blood pressure in Atg7 SM22α-Cre mice. Overall, our study indicates that apart from previously shown effects on large elastic arteries, VSMC autophagy also plays a pivotal role in the regulation of the contractile and relaxing properties of the smaller muscular arteries. This may suggest a role for autophagy in vascular pathologies, such as hypertension and arterial stiffness.
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http://dx.doi.org/10.3389/fphys.2020.548943DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7538838PMC
September 2020

Small molecule 3PO inhibits glycolysis but does not bind to 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 (PFKFB3).

FEBS Lett 2020 09 20;594(18):3067-3075. Epub 2020 Jul 20.

Laboratory of Physiopharmacology, University of Antwerp, Belgium.

6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase isoform 3 (PFKFB3) is a key enzyme of the glycolytic pathway, and it plays an essential role in angiogenesis. 3-(3-Pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3PO) is frequently used as a glycolysis inhibitor and is thought to inhibit PFKFB3. However, this latter effect of 3PO has never been investigated in detail and was the aim of the present study. To demonstrate binding of 3PO to PFKFB3, we used isothermal titration calorimetry. However, 3PO did not bind to PFKFB3, even up to 750 µm, in contrast to 3 µm of AZ67, which is a potent and specific PFKFB3 inhibitor. Instead, 3PO accumulated lactic acid inside the cells, leading to a decrease in the intracellular pH and an inhibition of enzymatic reactions of the glycolytic pathway.
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http://dx.doi.org/10.1002/1873-3468.13878DOI Listing
September 2020

Three-Dimensional Imaging of Intraplaque Neovascularization in a Mouse Model of Advanced Atherosclerosis.

J Vasc Res 2020 1;57(6):348-354. Epub 2020 Jul 1.

Laboratory of Physiopharmacology, University of Antwerp, Antwerp, Belgium,

Multiple lines of evidence suggest that intraplaque (IP) neovascularization promotes atherosclerotic plaque growth, destabilization, and rupture. However, pharmacological inhibition of IP neovascularization remains largely unexplored due to the limited number of animal models that develop IP neovessels and the lack of reliable methods for visualizing IP angiogenesis. Here, we applied 3D confocal microscopy with an optimized tissue-clearing process, immunolabeling-enabled three-dimensional imaging of solvent-cleared organs, to visualize IP neovessels in apolipoprotein E-deficient (ApoE-/-) mice carrying a heterozygous mutation (C1039+/-) in the fibrillin-1 gene. Unlike regular ApoE-/- mice, this mouse model is characterized by the presence of advanced plaques with evident IP neovascularization. Plaques were stained with antibodies against endothelial marker CD31 for 3 days, followed by incubation with fluorescently labeled secondary antibodies. Subsequent tissue clearing with dichloromethane (DCM)/methanol, DCM, and dibenzyl ether allowed easy visualization and 3D reconstruction of the IP vascular network while plaque morphology remained intact.
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http://dx.doi.org/10.1159/000508449DOI Listing
January 2021

INSPIRE: A European training network to foster research and training in cardiovascular safety pharmacology.

J Pharmacol Toxicol Methods 2020 Sep 18;105:106889. Epub 2020 Jun 18.

National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs), London, UK.

Safety pharmacology is an essential part of drug development aiming to identify, evaluate and investigate undesirable pharmacodynamic properties of a drug primarily prior to clinical trials. In particular, cardiovascular adverse drug reactions (ADR) have halted many drug development programs. Safety pharmacology has successfully implemented a screening strategy to detect cardiovascular liabilities, but there is room for further refinement. In this setting, we present the INSPIRE project, a European Training Network in safety pharmacology for Early Stage Researchers (ESRs), funded by the European Commission's H2020-MSCA-ITN programme. INSPIRE has recruited 15 ESR fellows that will conduct an individual PhD-research project for a period of 36 months. INSPIRE aims to be complementary to ongoing research initiatives. With this as a goal, an inventory of collaborative research initiatives in safety pharmacology was created and the ESR projects have been designed to be complementary to this roadmap. Overall, INSPIRE aims to improve cardiovascular safety evaluation, either by investigating technological innovations or by adding mechanistic insight in emerging safety concerns, as observed in the field of cardio-oncology. Finally, in addition to its hands-on research pillar, INSPIRE will organize a number of summer schools and workshops that will be open to the wider community as well. In summary, INSPIRE aims to foster both research and training in safety pharmacology and hopes to inspire the future generation of safety scientists.
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http://dx.doi.org/10.1016/j.vascn.2020.106889DOI Listing
September 2020

Defective autophagy in vascular smooth muscle cells increases passive stiffness of the mouse aortic vessel wall.

Pflugers Arch 2020 08 2;472(8):1031-1040. Epub 2020 Jun 2.

Laboratory of Physiopharmacology, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium.

Aging and associated progressive arterial stiffening are both important predictors for the development of cardiovascular diseases. Recent evidence showed that autophagy, a catabolic cellular mechanism responsible for nutrient recycling, plays a major role in the physiology of vascular cells such as endothelial cells and vascular smooth muscle cells (VSMCs). Moreover, several autophagy inducing compounds are effective in treating arterial stiffness. Yet, a direct link between VSMC autophagy and arterial stiffness remains largely unidentified. Therefore, we investigated the effects of a VSMC-specific deletion of the essential autophagy-related gene Atg7 in young mice (3.5 months) (Atg7 SM22α-Cre mice) on the biomechanical properties of the aorta, using an in-house developed Rodent Oscillatory Tension Set-up to study Arterial Compliance (ROTSAC). Aortic segments of Atg7 SM22α-Cre mice displayed attenuated compliance and higher arterial stiffness, which was more evident at higher distention pressures. Passive aortic wall remodeling, rather than differences in VSMC tone, is responsible for these phenomena, since differences in compliance and stiffness between Atg7 SM22α-Cre and Atg7 SM22α-Cre aortas were more pronounced when VSMCs were completely relaxed by the addition of exogenous nitric oxide. These observations are supported by histological data showing a 13% increase in medial wall thickness and a 14% decrease in elastin along with elevated elastin fragmentation. In addition, expression of the calcium-binding protein S100A4, which is linked to matrix remodeling, was elevated in aortic segments of Atg7 SM22α-Cre mice. Overall, these findings illustrate that autophagy exerts a crucial role in defining arterial wall compliance.
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http://dx.doi.org/10.1007/s00424-020-02408-yDOI Listing
August 2020

Partial Inhibition of Glycolysis Reduces Atherogenesis Independent of Intraplaque Neovascularization in Mice.

Arterioscler Thromb Vasc Biol 2020 05 19;40(5):1168-1181. Epub 2020 Mar 19.

From the Laboratory of Physiopharmacology (P.P., B.V.d.V., P.-J.G., G.R.Y.D.M., W.M.), University of Antwerp, Belgium.

Objective: Intraplaque neovascularization is an important feature of unstable human atherosclerotic plaques. However, its impact on plaque formation and stability is poorly studied. Because proliferating endothelial cells generate up to 85% of their ATP from glycolysis, we investigated whether pharmacological inhibition of glycolytic flux by the small-molecule 3PO (3-[3-pyridinyl]-1-[4-pyridinyl]-2-propen-1-one) could have beneficial effects on plaque formation and composition. Approach and Results: ApoE (apolipoprotein E deficient) mice treated with 3PO (50 µg/g, ip; 4×/wk, 4 weeks) showed a metabolic switch toward ketone body formation. Treatment of ApoEFbn1 mice with 3PO (50 µg/g, ip) either after 4 (preventive, twice/wk, 10 weeks) or 16 weeks of Western diet (curative, 4×/wk, 4 weeks) inhibited intraplaque neovascularization by 50% and 38%, respectively. Plaque formation was significantly reduced in all 3PO-treated animals. This effect was independent of intraplaque neovascularization. In vitro experiments showed that 3PO favors an anti-inflammatory M2 macrophage subtype and suppresses an M1 proinflammatory phenotype. Moreover, 3PO induced autophagy, which in turn impaired NF-κB (nuclear factor-kappa B) signaling and inhibited TNF-α (tumor necrosis factor-alpha)-mediated VCAM-1 (vascular cell adhesion molecule-1) and ICAM-1 (intercellular adhesion molecule-1) upregulation. Consistently, a preventive 3PO regimen reduced endothelial VCAM-1 expression in vivo. Furthermore, 3PO improved cardiac function in ApoEFbn1 mice after 10 weeks of treatment.

Conclusions: Partial inhibition of glycolysis restrained intraplaque angiogenesis without affecting plaque composition. However, less plaques were formed, which was accompanied by downregulation of endothelial adhesion molecules-an event that depends on autophagy induction. Inhibition of coronary plaque formation by 3PO resulted in an overall improved cardiac function.
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http://dx.doi.org/10.1161/ATVBAHA.119.313692DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7176341PMC
May 2020

Nitric oxide donor molsidomine favors features of atherosclerotic plaque stability and reduces myocardial infarction in mice.

Vascul Pharmacol 2019 Jul - Aug;118-119:106561. Epub 2019 May 11.

Laboratory of Physiopharmacology, University of Antwerp, Antwerp, Belgium. Electronic address:

Nitric oxide (NO) donors are commonly used for the prevention and treatment of ischemic heart disease. Besides their effects on the heart, NO donors may also prevent hypoxic brain damage and exert beneficial effects on atherosclerosis by favoring features of plaque stability. We recently described that apolipoprotein E (ApoE) deficient mice with a mutation in the fibrillin-1 (Fbn1) gene (ApoEFbn1) develop accelerated atherosclerosis, plaque rupture, myocardial infarction, cerebral hypoxia and sudden death. In the present study, we evaluated the effects of chronic treatment with the NO donor molsidomine on atherosclerotic plaque stability, cardiac function, neurological symptoms and survival in the ApoEFbn1 mouse model. Female ApoEFbn1 mice were fed a Western diet (WD). After 8 weeks of WD, the mice were divided into two groups receiving either molsidomine via the drinking water (1 mg/kg/day; n = 34) or tap water (control; n = 36) until 25 weeks of WD. Survival tended to increase after molsidomine treatment (68% vs. 58% in controls). Importantly, atherosclerotic plaques of molsidomine-treated mice had a thicker fibrous cap (11.1 ± 1.2 vs. 8.1 ± 0.7 μm) and showed an increased occurrence of plaque macrocalcifications (30% vs. 0%), indicative of a more stable phenotype. Molsidomine also improved cardiac function, as fractional shortening was increased (40 ± 2% vs. 27 ± 2%) combined with a decreased end diastolic (3.1 ± 0.2 vs. 3.9 ± 0.2 mm) and end systolic diameter (1.9 ± 0.1 vs. 2.9 ± 0.2 mm). Furthermore, perivascular fibrosis (23 ± 2 vs. 30 ± 2%) and the occurrence of myocardial infarctions (12% vs. 36%) was significantly reduced. Track width, a measure of the animal's hind limb base of support and representative of hypoxic brain damage, was also normalized as a result of molsidomine treatment (2.54 ± 0.04 vs. 2.91 ± 0.09 cm in controls). These findings demonstrate that the NO donor molsidomine improves cardiac function, reduces neurological symptoms and enhances atherosclerotic plaque stability.
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http://dx.doi.org/10.1016/j.vph.2019.05.001DOI Listing
May 2020

Macrophage Death as a Pharmacological Target in Atherosclerosis.

Front Pharmacol 2019 4;10:306. Epub 2019 Apr 4.

Laboratory of Physiopharmacology, University of Antwerp, Antwerp, Belgium.

Atherosclerosis is a chronic inflammatory disorder characterized by the gradual build-up of plaques within the vessel wall of middle-sized and large arteries. Over the past decades, treatment of atherosclerosis mainly focused on lowering lipid levels, which can be accomplished by the use of statins. However, some patients do not respond sufficiently to statin therapy and therefore still have a residual cardiovascular risk. This issue highlights the need for novel therapeutic strategies. As macrophages are implicated in all stages of atherosclerotic lesion development, they represent an important alternative drug target. A variety of anti-inflammatory strategies have recently emerged to treat or prevent atherosclerosis. Here, we review the canonical mechanisms of macrophage death and their impact on atherogenesis and plaque stability. Macrophage death is a prominent feature of advanced plaques and is a major contributor to necrotic core formation and plaque destabilization. Mechanisms of macrophage death in atherosclerosis include apoptosis, passive or accidental necrosis as well as secondary necrosis, a type of death that typically occurs when apoptotic cells are insufficiently cleared by neighboring cells via a phagocytic process termed efferocytosis. In addition, less-well characterized types of regulated necrosis in macrophages such as necroptosis, pyroptosis, ferroptosis, and parthanatos may occur in advanced plaques and are also discussed. Autophagy in plaque macrophages is an important survival pathway that protects against cell death, yet massive stimulation of autophagy promotes another type of death, usually referred to as autosis. Multiple lines of evidence indicate that a better insight into the different mechanisms of macrophage death, and how they mutually interact, will provide novel pharmacological strategies to resolve atherosclerosis and stabilize vulnerable, rupture-prone plaques.
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http://dx.doi.org/10.3389/fphar.2019.00306DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6458279PMC
April 2019

Hormonal contraception without a prescription: opinions of pharmacists, general practitioners and gynaecologists in Flanders, Belgium.

Eur J Contracept Reprod Health Care 2019 Apr 1;24(2):85-96. Epub 2019 Apr 1.

a Laboratory of Physiopharmacology , University of Antwerp , Antwerp , Belgium.

Objective: The accessibility of contraceptives varies greatly from country to country. Because unintended pregnancies have a considerable impact, programmes have been initiated in some countries to make certain contraceptives available without a prescription. We therefore investigated whether or not Flanders, the Dutch-speaking part of Belgium, is ready for such an initiative.

Method: We used a mixed-methods approach with a mainly qualitative methodology. The opinions of pharmacists, general practitioners (GPs) and gynaecologists, the three types of health care provider most closely involved in the prescription and delivery of contraception, were examined.

Results: A majority of pharmacists supported the idea. Moreover, a large majority occasionally dispensed hormonal contraception without a prescription. Pharmacists expected negative responses from physicians. Among GPs and gynaecologists, a small majority supported the idea conditionally. A minority either fully supported the idea or found it completely unacceptable.

Conclusion: Economic aspects were clearly important in forming an opinion on the topic, although medical arguments were often used when they happened to point in the same direction. Flemish pharmacists were willing to train for and implement a new service that would provide contraceptives without a prescription. The majority of GPs and gynaecologists expressed reservations about such a service and doubted that it would reduce unintended pregnancies. If this service were to be implemented, caution would be needed to avoid giving contraceptive users conflicting information.
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http://dx.doi.org/10.1080/13625187.2019.1595574DOI Listing
April 2019

Dietary Polyphenols Targeting Arterial Stiffness: Interplay of Contributing Mechanisms and Gut Microbiome-Related Metabolism.

Nutrients 2019 Mar 8;11(3). Epub 2019 Mar 8.

Laboratory of Natural Products and Food-Research and Analysis (NatuRA), University of Antwerp, 2610 Antwerpen, Belgium.

Increased arterial stiffness is a degenerative vascular process, progressing with age that leads to a reduced capability of arteries to expand and contract in response to pressure changes. This progressive degeneration mainly affects the extracellular matrix of elastic arteries and causes loss of vascular elasticity. Recent studies point to significant interference of dietary polyphenols with mechanisms involved in the pathophysiology and progression of arterial stiffness. This review summarizes data from epidemiological and interventional studies on the effect of polyphenols on vascular stiffness as an illustration of current research and addresses possible etiological factors targeted by polyphenols, including pathways of vascular functionality, oxidative status, inflammation, glycation, and autophagy. Effects can either be inflicted directly by the dietary polyphenols or indirectly by metabolites originated from the host or microbial metabolic processes. The composition of the gut microbiome, therefore, determines the resulting metabolome and, as a consequence, the observed activity. On the other hand, polyphenols also influence the intestinal microbial composition, and therefore the metabolites available for interaction with relevant targets. As such, targeting the gut microbiome is another potential treatment option for arterial stiffness.
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http://dx.doi.org/10.3390/nu11030578DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6471395PMC
March 2019

Vascular smooth muscle cell contraction and relaxation in the isolated aorta: a critical regulator of large artery compliance.

Physiol Rep 2019 02;7(4):e13934

Laboratory of Physiopharmacology, Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium.

Over the past few decades, isometric contraction studies of isolated thoracic aorta segments have significantly contributed to our overall understanding of the active, contractile properties of aortic vascular smooth muscle cells (VSMCs) and their cross-talk with endothelial cells. However, the physiological role of VSMC contraction or relaxation in the healthy aorta and its contribution to the pulse-smoothening capacity of the aorta is currently unclear. Therefore, we investigated the acute effects of VSMC contraction and relaxation on the isobaric biomechanical properties of healthy mouse aorta. An in-house developed set-up was used to measure isobaric stiffness parameters of periodically stretched (10 Hz) aortic segments at an extended pressure range, while pharmacologically modulating VSMC tone and endothelial cell function. We found that the effects of α1-adrenergic stimulation with phenylephrine on the pressure-stiffness relationship varied in sensitivity, magnitude and direction, with the basal, unstimulated NO production by the endothelium playing a pivotal role. We also investigated how arterial disease affected this system by using the angiotensin-II-treated mouse. Our results show that isobaric stiffness was increased and that the aortic segments demonstrated a reduced capacity for modulating the pressure-stiffness relationship. This suggests that not only increased isobaric stiffness at normal pressure, but also a reduced capacity of the VSMCs to limit the pressure-associated increase in aortic stiffness, may contribute to the pathogenesis of this mouse model. Overall, this study provides more insight in how aortic VSMC tone affects the pressure-dependency of aortic biomechanics at different physiological and pathological conditions.
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http://dx.doi.org/10.14814/phy2.13934DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6391714PMC
February 2019

Everolimus depletes plaque macrophages, abolishes intraplaque neovascularization and improves survival in mice with advanced atherosclerosis.

Vascul Pharmacol 2019 Feb 24;113:70-76. Epub 2018 Dec 24.

Laboratory of Physiopharmacology, Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium. Electronic address:

Background And Aims: Inhibition of the mechanistic target of rapamycin (mTOR) is a promising approach to halt atherogenesis in different animal models. This study evaluated whether the mTOR inhibitor everolimus can stabilize pre-existing plaques, prevent cardiovascular complications and improve survival in a mouse model of advanced atherosclerosis.

Methods: ApoEFbn1 mice (n = 24) were fed a Western diet (WD) for 12 weeks. Subsequently, mice were treated with everolimus (1.5 mg/kg daily) or vehicle for another 12 weeks while the WD continued.

Results: Despite hypercholesterolemia, everolimus treatment was associated with a reduction in circulating Ly6C monocytes (15 vs. 28% of total leukocytes, p = 0.046), a depletion of plaque macrophages (2.1 vs. 4.1%, p = 0.040) and an abolishment of intraplaque neovascularization, which are all indicative of a more stable plaque phenotype. Moreover, everolimus reduced hypoxic brain damage and improved cardiac function, which led to increased survival (100 vs. 67% of animals, p = 0.038).

Conclusions: Everolimus enhances features of plaque stability and counters cardiovascular complications in ApoEFbn1 mice, even when administered at a later stage of the disease.
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http://dx.doi.org/10.1016/j.vph.2018.12.004DOI Listing
February 2019

Pharmacological strategies to inhibit intra-plaque angiogenesis in atherosclerosis.

Vascul Pharmacol 2019 01 19;112:72-78. Epub 2018 Jun 19.

Laboratory of Physiopharmacology, University of Antwerp, Belgium. Electronic address:

Atherosclerosis is a complex multifactorial disease that affects large and medium-sized arteries. Rupture of atherosclerotic plaques and subsequent acute cardiovascular complications remain a leading cause of death and morbidity in the Western world. There is a considerable difference in safety profile between a stable and a vulnerable, rupture-prone lesion. The need for plaque-stabilizing therapies is high, and for a long time the lack of a suitable animal model mimicking advanced human atherosclerotic plaques made it very difficult to make progress in this area. Evidence from human plaques indicates that intra-plaque (IP) angiogenesis promotes atherosclerosis and plaque destabilization. Although neovascularization has been widely investigated in cancer, studies on the pharmacological inhibition of this phenomenon in atherosclerosis are scarce, mainly due to the lack of an appropriate animal model. By using ApoE Fbn1 mice, a novel model of vulnerable plaques, we were able to investigate the effect of pharmacological inhibition of various mechanisms of IP angiogenesis on plaque destabilization and atherogenesis. In the present review, we discuss the following potential pharmacological strategies to inhibit IP angiogenesis: (1) inhibition of vascular endothelial growth factor signalling, (2) inhibition of glycolytic flux, and (3) inhibition of fatty acid oxidation. On the long run, IP neovascularization might be applicable as a therapeutic target to induce plaque stabilization on top of lipid-lowering treatment.
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http://dx.doi.org/10.1016/j.vph.2018.06.014DOI Listing
January 2019

Cellular senescence links aging and diabetes in cardiovascular disease.

Am J Physiol Heart Circ Physiol 2018 09 11;315(3):H448-H462. Epub 2018 May 11.

Laboratory of Physiopharmacology, University of Antwerp , Antwerp , Belgium.

Aging is a powerful independent risk factor for cardiovascular diseases such as atherosclerosis and heart failure. Concomitant diabetes mellitus strongly reinforces this effect of aging on cardiovascular disease. Cellular senescence is a fundamental mechanism of aging and appears to play a crucial role in the onset and prognosis of cardiovascular disease in the context of both aging and diabetes. Senescent cells are in a state of cell cycle arrest but remain metabolically active by secreting inflammatory factors. This senescence-associated secretory phenotype is a trigger of chronic inflammation, oxidative stress, and decreased nitric oxide bioavailability. A complex interplay between these three mechanisms results in age- and diabetes-associated cardiovascular damage. In this review, we summarize current knowledge on cellular senescence and its secretory phenotype, which might be the missing link between aging and diabetes contributing to cardiovascular disease.
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http://dx.doi.org/10.1152/ajpheart.00287.2018DOI Listing
September 2018

Defective Autophagy in Atherosclerosis: To Die or to Senesce?

Oxid Med Cell Longev 2018 26;2018:7687083. Epub 2018 Feb 26.

Laboratory of Physiopharmacology, University of Antwerp, Antwerp, Belgium.

Autophagy is a subcellular process that plays an important role in the degradation of proteins and damaged organelles such as mitochondria (a process termed "mitophagy") via lysosomes. It is crucial for regulating protein and mitochondrial quality control and maintaining cellular homeostasis, whereas dysregulation of autophagy has been implicated in a wide range of diseases including atherosclerosis. Recent evidence has shown that the autophagic process becomes dysfunctional during the progression of atherosclerosis, regardless of whether there are many autophagy-stimulating factors (e.g., reactive oxygen species, oxidized lipids, and cytokines) present within the atherosclerotic plaque. This review highlights the recent insights into the causes and consequences of defective autophagy in atherosclerosis, with a special focus on the role of autophagy and mitophagy in plaque macrophages, vascular smooth muscle cells (VSMCs), and endothelial cells (ECs). It has been shown that defective autophagy can promote apoptosis in macrophages but that it accelerates premature senescence in VSMCs. In the ECs, defective autophagy promotes both apoptosis and senescence. We will discuss the discrepancy between these three cell types in their response to autophagy deficiency and underline the cell type-dependent role of autophagy, which may have important implications for the efficacy of autophagy-targeted treatments for atherosclerosis.
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http://dx.doi.org/10.1155/2018/7687083DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5846382PMC
September 2018

Novel drug discovery strategies for atherosclerosis that target necrosis and necroptosis.

Expert Opin Drug Discov 2018 06 29;13(6):477-488. Epub 2018 Mar 29.

a Laboratory of Physiopharmacology , University of Antwerp , Wilrijk , Belgium.

Introduction: Formation and enlargement of a necrotic core play a pivotal role in atherogenesis. Since the discovery of necroptosis, which is a regulated form of necrosis, prevention of necrotic cell death has become an attractive therapeutic goal to reduce plaque formation. Areas covered: This review highlights the triggers and consequences of (unregulated) necrosis and necroptosis in atherosclerosis. The authors discuss different pharmacological strategies to inhibit necrotic cell death in advanced atherosclerotic plaques. Expert opinion: Addition of a necrosis or necroptosis inhibitor to standard statin therapy could be a promising strategy for primary prevention of cardiovascular disease. However, a necrosis inhibitor cannot block all necrosis stimuli in atherosclerotic plaques. A necroptosis inhibitor could be more effective, because necroptosis is mediated by specific proteins, termed receptor-interacting serine/threonine-protein kinases (RIPK) and mixed lineage kinase domain-like pseudokinase (MLKL). Currently, only RIPK1 inhibitors have been successfully used in atherosclerotic mouse models to inhibit necroptosis. However, because RIPK1 is involved in both necroptosis and apoptosis, and also RIPK1-independent necroptosis can occur, we feel that targeting RIPK3 and MLKL could be a more attractive therapeutic approach to inhibit necroptosis. Therefore, future challenges will consist of developing RIPK3 and MLKL inhibitors applicable in both preclinical and clinical settings.
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http://dx.doi.org/10.1080/17460441.2018.1457644DOI Listing
June 2018

Neuregulin-1 attenuates stress-induced vascular senescence.

Cardiovasc Res 2018 06;114(7):1041-1051

Laboratory of Physiopharmacology, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium.

Aims: Cardiovascular ageing is a key determinant of life expectancy. Cellular senescence, a state of irreversible cell cycle arrest, is an important contributor to ageing due to the accumulation of damaged cells. Targeting cellular senescence could prevent age-related cardiovascular diseases. In this study, we investigated the effects of neuregulin-1 (NRG-1), an epidermal growth factor with cardioprotective and anti-atherosclerotic effects, on cellular senescence.

Methods And Results: Senescence was induced in cultured rat aortic endothelial cells (ECs) and aortic smooth muscle cells (SMCs) by 2 h exposure to 30 µM hydrogen peroxide (H2O2). Cellular senescence was confirmed after 72 h using senescence-associated-β-galactosidase staining (SA-β-gal), cell surface area, and western blot analyses of SA pathways (acetyl-p53, p21). Recombinant human NRG-1 (rhNRG-1, 20 ng/mL) significantly reduced H2O2-induced senescence, as shown by a lower number of SA-β-gal positive cells, smaller surface area and lower expression of acetyl-p53. In C57BL/6 male mice rendered diabetic with streptozotocin (STZ), rhNRG-1 attenuated cellular senescence in aortic ECs and SMCs. Next, we created mice with SMC-specific knockdown of the NRG-1 receptor ErbB4. Aortic SMCs isolated from SMC-specific ErbB4 deficient mice (ErbB4f/+ SM22α-Cre+) showed earlier cellular senescence in vitro compared with wild-type (ErbB4+/+ SM22α-Cre+) SMCs. Furthermore, when rendered diabetic with STZ, ErbB4f/+ SM22α-Cre+ male mice showed significantly more vascular senescence than their diabetic wild-type littermates and had increased mortality.

Conclusions: This study is the first to explore the role of NRG-1 in vascular senescence. Our data demonstrate that NRG-1 markedly inhibits stress-induced premature senescence in vascular cells in vitro and in the aorta of diabetic mice in vivo. Consistently, deficiency in the NRG-1 receptor ErbB4 provokes cellular senescence in vitro as well as in vivo.
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http://dx.doi.org/10.1093/cvr/cvy059DOI Listing
June 2018

Vascular smooth muscle cell death, autophagy and senescence in atherosclerosis.

Cardiovasc Res 2018 03;114(4):622-634

Laboratory of Physiopharmacology, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium.

In the present review, we describe the causes and consequences of loss of vascular smooth muscle cells (VSMCs) or their function in advanced atherosclerotic plaques and discuss possible mechanisms such as cell death or senescence, and induction of autophagy to promote cell survival. We also highlight the potential use of pharmacological modulators of these processes to limit plaque progression and/or improve plaque stability. VSMCs play a pivotal role in atherogenesis. Loss of VSMCs via initiation of cell death leads to fibrous cap thinning and promotes necrotic core formation and calcification. VSMC apoptosis is induced by pro-inflammatory cytokines, oxidized low density lipoprotein, high levels of nitric oxide and mechanical injury. Apoptotic VSMCs are characterized by a thickened basal lamina surrounding the cytoplasmic remnants of the VSMC. Inefficient clearance of apoptotic VSMCs results in secondary necrosis and subsequent inflammation. A critical determinant in the VSMC stress response and phenotypic switching is autophagy, which is activated by various stimuli, including reactive oxygen and lipid species, cytokines, growth factors and metabolic stress. Successful autophagy stimulates VSMC survival, whereas reduced autophagy promotes age-related changes in the vasculature. Recently, an interesting link between autophagy and VSMC senescence has been uncovered. Defective VSMC autophagy accelerates not only the development of stress-induced premature senescence but also atherogenesis, albeit without worsening plaque stability. VSMC senescence in atherosclerosis is likely a result of replicative senescence and/or stress-induced premature senescence in response to DNA damaging and/or oxidative stress-inducing stimuli. The finding that VSMC senescence can promote atherosclerosis further illustrates that normal, adequate VSMC function is crucial in protecting the vessel wall against atherosclerosis.
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http://dx.doi.org/10.1093/cvr/cvy007DOI Listing
March 2018

Cytoprotective effects of transgenic neuroglobin overexpression in an acute and chronic mouse model of ischemic heart disease.

Heart Vessels 2018 Jan 2;33(1):80-88. Epub 2017 Nov 2.

Protein Chemistry, Proteomics and Epigenetic Signalling, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium.

Neuroglobin (NGB) is an oxygen-binding protein that is mainly expressed in nervous tissues where it is considered to be neuroprotective during ischemic brain injury. Interestingly, transgenic mice overexpressing NGB reveal cytoprotective effects on tissues lacking endogenous NGB, which might indicate a therapeutic role for NGB in a broad range of ischemic conditions. In the present study, we investigated the effect of NGB overexpression on survival as well as on the size and occurrence of myocardial infarctions (MI) in a mouse model of acute MI (AMI) and a model of advanced atherosclerosis (ApoE Fbn1 mice), in which coronary plaques and MI develop in mice being fed a Western-type diet. Overexpression of NGB significantly enhanced post-AMI survival and reduced MI size by 14% 1 week after AMI. Gene expression analysis of the infarction border showed reduction of tissue hypoxia and attenuation of hypoxia-induced inflammatory pathways, which might be responsible for these beneficial effects. In contrast, NGB overexpression did not affect survival or occurrence of MI in the atherosclerotic mice although the incidence of coronary plaques was significantly reduced. In conclusion, NGB proved to act cytoprotectively during MI in the acute setting while this effect was less pronounced in the atherosclerosis model.
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http://dx.doi.org/10.1007/s00380-017-1065-5DOI Listing
January 2018
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