bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acute dietary saturated fat intake suppresses human monocyte subset inflammatory and chemokine responses
Authors: Rahman M.S , Haskard D.O , Frost G , Vorkas P , Woollard K.J 
Published: November 2020

Abstract

Background
Dietary saturated fat (SF) intake is implicated in increasing cardiovascular risk. Studies suggest SF may incite an inflammatory immune response yet the mechanisms for this remain unclear. Circulating blood monocyte subsets (classical “CD16low” and non-classical/intermediate “CD16high”) are thought to differentially contribute to the macrophage foam cell burden in atherosclerotic plaque, yet they are heterogenous and much is still unknown about their response to dietary lipid.

Purpose
This dietary intervention study hypothesised that a subset-specific monocyte response occurs following acute SF intake in healthy individuals.Top of Form

Methods
10 healthy participants were fed a coconut oil, lauric acid-rich meal. Monocyte subsets were purified from fasting and 4h postprandial blood by fluorescence activated cytometry (FACS) into CD16low and CD16high subsets. Surface marker expression was recorded by FACS, gene expression by qPCR, lipid loading by fluorescence microscopy, cytokine responses by ELISA and mass spectrometry was utilised to trace dietary fat into circulating monocytes. Triglyceride rich lipoprotein (TGRL) was obtained through ultracentrifugation of postprandial blood. TLR agonists LPS (TLR4) and R848 (TLR7/8) were used to replicate infectious stimuli to provoke a cytokine response.

Results
SF meal intake resulted in a 4h postprandial rise in serum triglycerides (TG). Other than a small rise in HLA-DR in postprandial CD16low monocytes, no changes in CD14, CD16 or CD11c levels were noted. Inflammatory gene expression was downregulated although a rise in lipid handling gene ABCA1 was noted in both subsets. Postprandial monocytes accumulated cytoplasmic neutral lipid droplets (larger and more numerate droplets in CD16low). Mass-spectrometry confirmed entry of dietary lipid into circulating monocytes. Postprandial monocyte functional responses were impaired; lipid-loaded postprandial monocytes were less able to migrate towards a chemokine gradient. Following TLR challenge, the inflammatory response was abrogated in postprandial monocytes, further suppressed by in vitro postprandial TGRL addition. Lipidomic analyses confirmed postprandial monocyte lauric acid accumulation in the form of free fatty acid and TG trilaurin, and 9(S)-, 13(S)-HODE and 17(S)-HDoHE, that are metabolites of docosahexanoic acid (DHA) and possess anti-inflammatory properties. The attached graphical abstract summarises the pertinent findings.

Conclusions
Acute dietary SF intake of a lauric acid-rich meal results in postprandial monocyte suppression of inflammatory TLR responses, a reduction in the ability to migrate towards a chemokine gradient whilst accumulating cytoplasmic neutral lipid droplets. The immunosuppression may be caused by accumulation of anti-inflammatory metabolites of DHA.
Graphical Abstract

Funding Acknowledgement
Type of funding source: Foundation. Main funding source(s): British Heart Foundation, UK
m6A methyltransferase RBM15 promotes cardiomyocytes survival under hypoxia by increasing Thbs4 RNA methylation and mediating PI3K/Akt signaling
Authors: Cheng H , Song X.Y , Xue J.Q , Chen L , Xu R.D , Qian J.Y , Zou Y.Z , Ma J.Y , Ge J.B 
Published: November 2020

Abstract

Background
mRNA modifications constitute ancient mechanisms in regulating gene expression after transcription. N6-methyladenosis (m6A), which is the most prevalent internal RNA modification, is not only installed by m6A methyltransferases, removed by demethylases, but also specifically bounded by RNA-binding proteins. As a significant component in the m6A methyltransferase complex, RNA binding motif protein 15 (RBM15) plays a vital role in m6A methylation. Nevertheless, its function and mechanism in myocardial infarction (MI) remain poorly defined.

Purpose
To investigate the role and mechanism of RBM15 in regulating its targets through m6A methylation in MI. The research results will not only add new content to the basic mechanism of myocardial protection but also provide new ideas and new targets for the prevention and treatment of MI.

Methods
Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to clarify the total m6A level, and Reverse transcription quantitative real-time PCR (RT-qPCR) and Western blot were used to determine the expression of RBM15 in normal and MI tissues. Then the effects of RBM15 on cardiomyocytes were clarified using apoptosis assay, and cell proliferation assay. Methylated RNA immunoprecipitation sequencing (MeRIP-seq), and transcriptomic RNA sequencing (RNA-seq) were used to perform the regulator mechanism of RBM15 on target gene Thbs4 in MI.

Results
In this research, we showed that total m6A methylation was increased in MI, and RBM15 was a main factor involved with this process. Silencing RBM15 remarkably decreased cell proliferation and increased apoptosis in vitro, and resulted in severe cardiac remodeling and further exacerbation of cardiac dysfunction in vivo, whereas its overexpression caused the opposite effects. Then, Thbs4 was identified as a direct downstream target of RBM15, and RBM15 induced m6A methylation on the 3'UTR of Thbs4 pre-mRNA. We also found that it showed faster Thbs4 mRNA decay and exhibited decreased mRNAs and levels of protein expression in RBM15-deficient cardiomyocytes under hypoxia. Furthermore, we confirmed that RBM15 contributed significantly to regulate the PI3k/Akt pathway.

Conclusions
Our work uncovers a complex RBM15-Thbs4-PI3K/Akt regulatory model based on m6A methylation and provides a new insight into the epi-transcriptomic dysregulation in MI development.

Funding Acknowledgement
Type of funding source: Public grant(s) – National budget only. Main funding source(s): National Natural Science Foundation of China
A meta-analysis of the transcriptional landscape of end stage heart failure with reduced ejection fraction
Authors: Lanzer J , Ramirez-Flores R , Schultz J.H , Levinson R , Saez-Rodriguez J 
Published: November 2020

Abstract

During heart failure (HF) the myocardium undergoes ventricular remodeling, which is accompanied by changes in gene expression. Transcriptomic studies have contributed to fundamental knowledge of this remodeling. However many studies do not agree on the differentially expressed marker genes. We hypothesized that a comprehensive meta-analysis of available studies would help to address this incongruence.
We curated and uniformly processed 14 public transcriptomic data sets consisting of left ventricular samples from 265 healthy and 642 failing hearts. We assessed their comparability by applying transfer learning based classifiers. We then combined all datasets to extract a consensus gene signature. Combining this consensus signature with biological prior knowledge, we estimated transcription factor activities with DoRothEA and pathway activities by footprint analysis with PROGENy.
Although single studies reported highly dissimilar marker genes, transfer knowledge based approaches revealed that disease patterns are conserved across studies. We derived a gene ranking that reflects consistent molecular hallmarks of HF. The ranking is strongly enriched in fibrosis related gene sets and contains significant (all p-values &lt;0.05) footprints of numerous transcription factors including Nanog, Sox2, Pbx3, Mef2; pathways including Jak-Stat and miRNAs including MIR-206, MIR-514.
We demonstrated the feasibility of combining transcriptional studies from different technologies, years and centers. We extracted a consensus gene signature as a valuable resource to understand common molecular patterns in HF. To our knowledge, this report represents the largest meta-analysis of transcriptional HF studies to date.
Selected transcription factor (TF) activities derived via footprint analysis from the consensus gene ranking TF NES Size P-value SOX2 6.3 179 2.59E-10 MYNN −5.7 347 8.14E-09 MTA2 −5.3 29 9.1E-08 ZBTB7A 4.8 66 1.25E-06 BL3 −4.5 26 5.46E-06 ZEB2 −3.9 46 8.99E-05 NANOG 3.81 34 0.00047 PBX3 3.4 41 0.0005 MEF2C 3.1 55 0.001602 MEIS2 2.7 718369 0.00656 NES, normalized enrichment score; size, regulon size.
Graphical summary

Funding Acknowledgement
Type of funding source: Foundation. Main funding source(s): Klaus Tschirer Stiftung
Abnormal P-waves found in patients with sleep-disordered breathing are associated with triggered pro-arrhythmic activity
Authors: Lebek S , Wester M , Tafelmeier M , Fisser C , Hirt S , Schopka S , Schmid C , Maier L.S , Arzt M , Wagner S 
Published: November 2020

Abstract

Background
Sleep-disordered breathing (SDB) is frequently associated with atrial arrhythmias, but diagnostic markers that predict the propensity for atrial arrhythmias are missing. Abnormal P-wave terminal force in lead V1 (PTFV1) has been associated with atrial structural/electrical remodeling and arrhythmias.

Purpose
Here we investigate the association of triggered pro-arrhythmic activity with abnormal PTFV1 in human right atrial appendage biopsies of patients without and with SDB.

Methods
30 patients undergoing elective coronary artery bypass grafting were screened for SDB by polygraphy. An apnoea-hypopnea index (AHI) of ≥15/h defined SDB. PTFV1 was measured as product of negative P-wave amplitude and duration in lead V1 and was defined as abnormal if &gt;4000 ms*μV. Ca/Calmodulin-dependent protein kinase II (CaMKII) activity was measured in human right atrial appendage biopsies by a specific HDAC4 pull-down assay. Premature atrial contractions (PACs) were triggered by exposure to 100 nM isoproterenol (at 3.5 mM [Ca]o) in human atrial trabeculae. PACs severity was classified by a score from 0 points (no arrhythmias) to 5 points (salve). In addition, atrial fibrosis was quantified by Masson's trichrome stain in cryo-sectioned atrial tissue. Multivariate linear regression analyses were performed accounting for age, sex, BMI, existing AF, heart failure, diabetes, and creatinine.

Results
Interestingly, the AHI was independently associated with the magnitude of PTFV1 (fig. A+B, B=57.47±21.03, R2=0.48, P=0.01). Importantly, patients with an abnormal PTFV1 had a significantly increased CaMKII activity (fig. C, P=0.04) and showed significantly more severe triggered PACs (fig. D, P=0.02). Moreover, the magnitude of PTFV1 correlated significantly and independently with PAC severity (fig. D, B=0.0005±0.0002, R2=0.50, P=0.03). Consistently, these arrhythmias could be significantly reduced by acute CaMKII inhibition (5 μM KN93, P&lt;0.01), which abolished the correlation between PTFV1 and PAC severity (P=N.S.). Surprisingly, atrial fibrosis was significantly decreased in patients with an abnormal PTFV1 (fig. E, P=0.02), suggesting that abnormal PTFV1 is a marker of proarrhythmic atrial electrical remodeling of functional cardiomyocytes but not of fibrotic tissue.

Conclusion
The severity of sleep-disordered breathing (AHI) is independently associated with an abnormal PTFV1. Intriguingly, this abnormality is associated with an increased CaMKII activity and with CaMKII-dependent arrhythmias, suggesting PTFV1 to be a potential tool to evaluate the pro-arrhythmic risk of patients with SDB.
Figure 1

Funding Acknowledgement
Type of funding source: Private company. Main funding source(s): Part of this study was funded by Philips Respironics.
Acute and chronic cholinergic activity in the inflammatory and lipid regulation of epicardial stromal cells from patients with and without atrial fibrillation
Authors: Couselo Seijas M , Fu X , Lopez-Cano J.N , Rozados-Luis A , Fernandez A.L , Seoane L.M , Duran-Munoz D , Gonzalez-Melchor L , Rodriguez-Manero M , Gonzalez-Juanatey J.R , Eiras S 
Published: November 2020

Abstract

Aims
Acetylcholine (ACh) released modulation by botulinum toxin injection into epicardial fat diminish atrial fibrillation (AF) recurrence. These results suggest an interaction between autonomic imbalance and epicardial fat as risk factors of AF. Our aim was to study the inflammatory and lipid profile of epicardial stroma from AF patients and their regulation by high cholinergic activity.

Methods and results
We performed in vitro assays with primary cultures from paired subcutaneous and epicardial stromal cells from 33 patients. We analysed ACh effect on gene expression, intracellular calcium mobilization and neutrophil migration. Plasma protein regulation by parasympathetic denervation was performed in vagotomised rats. Acute ACh treatment up-regulated MCP1 levels on epicardial stromal cells and suggested a neutrophil infiltration enhancement. Patients with AF had a greater FABP4 gene expression (1.54±0.01 vs 1.47±0.01, p=0.005). Its plasma levels were pronouncedly declined on vagotomised rats (2.02±0.21 ng/mL vs 0.65±0.23 ng/mL, p&lt;0.001). Additionally, chronic ACh treatment improved lipid accumulation within epicardial stromal cells (60.50% [22.82–85.13] vs 13.85% [6.17–23.16], p&lt;0.001).

Conclusions
Acute ACh activity up-regulates MCP1 and calcium mobilization on epicardial stromal cells. Longer ACh treatment enhanced lipid accumulation. In this line, epicardial stroma from patients with permanent AF contains higher FABP4 expression levels. Thus, modulate cholinergic activity might reduce FABP4 since vagus nerve denervation is associated with a sharply decrease in FABP4 plasma levels.
FABP4 in human AF and vagotomised rats

Funding Acknowledgement
Type of funding source: Public Institution(s). Main funding source(s): Carlos III Health Institute; Health Research Institute of Santiago de Compostela
Pharmacological inhibition of acetylcholine-regulated potassium current (IK,ACh) and associated A1- and M2-pathways prevent atrial arrhythmogenic changes in a rat model for obstructive sleep apnea
Authors: Linz B , Hauge Thostrup A , Saljic A , Rombouts K , Wirth K , Hohl M , Linz D , Jespersen T 
Published: November 2020

Abstract

Background
In obstructive sleep apnea (OSA), intermittent hypoxemia and intrathoracic pressure fluctuations may increase vagal tone and adenosine release, potentially resulting in an increased acetylcholine-regulated potassium current (IK,ACh). Here we elucidated acute atrial electrophysiological effects of obstructive respiratory events simulated by intermittent negative upper airway pressure (INAP) and the role of atrial IKACh activation by A1-receptor and M2-receptor activation.

Methods
In sedated spontaneously breathing rats (2% isoflurane), either IK,ACh-inhibitor (XAF-1407: 1mg/kg), M2-receptor inhibitor (atropine; 1μg/kg), A1-receptor inhibitor (Rolofylline; 1μg/kg) or a buffer-based vehicle was perfused (Control). INAP was applied non-invasively by a negative pressure device 14 times throughout 70 minutes. Simulated apneas were maintained for one minute with a four minute resting period. Atrial effective refractory period (AERP) and atrial activation time were acquired by a programmed atrial pacing protocol before, during and after applied INAP throughout the study.

Results
Independent of IK,Ach-inhibition, single INAP applications prolonged transiently atrial activation times (Control: INAP vs. pre-INAP p=0.034; XAF-1407: INAP vs. pre-INAP p=0.039). In control-rats, seventy minutes of repetitive INAP decreased AERP by 15.45±0.06% (vs. baseline p=0.0015), which was reversible upon 1 hour of recovery. AERP shortening correlated with the cumulative pressure applied per body weight (Pearson r=−0.773; p=0.025). Whilst only XAF-1407 and atropine increased baseline AERP, all drug interventions, XAF-1407, atropine and Rolofylline could prevent INAP-associated AERP shortening (end INAP-protocol vs. respective baseline XAF-1407 p=0.994; atropine p=0.984; Rolofylline p=0.951). Drops in oxygen saturation and applied INAP were comparable in all groups.

Conclusion
Short-term simulated OSA is associated with progressive AERP shortening, which was determined by the cumulative negative airway pressure applied. This potentially represents an important insight in future OSA treatment. Pharmacological IK,ACh inhibition prevented INAP-associated AERP-shortening suggesting an involvement in acute atrial arrhythmogenesis in OSA. However, if IK,Ach and its potential upstream activating A1- and M2-pathway pose a pharmacological treatment target for OSA-patients with AF, requires further investigation.

Funding Acknowledgement
Type of funding source: None
New ex vivo calcification model for intact murine aortic valves
Authors: Kruithof B , Van De Pol V , Los T , Lodder K , De Ruiter M.C , Goumans M.J , Schalij M.J , Ajmone Marsan N 
Published: November 2020

Abstract

Introduction
Calcific aortic valve disease (CAVD) is a common, progressive disease of the aortic valves for which no medical treatment exists and surgery is the only therapeutic solution. The discovery of novel pharmacological treatment for CAVD has been hampered due to the lack of suitable test-systems.

Purpose
We aimed to establish an ex vivo calcification model for intact mouse aortic valves.

Methods
We used the ex vivo flow model for mouse hearts (Miniature Tissue Culture System) to induce calcification with culture media supplemented with 1) β-glycerophosphate, ascorbic acid, and dexamethasone (OSM) or 2) inorganic phosphates (PI) and compared this with in vitro calcification of mouse valvular interstitial cells (mVICs).

Results
Ex vivo cultured aortic valve leaflets calcified in the presence of PI, but not OSM. RUNX was upregulated in both OSM and PI conditions, whereas alkaline phosphatase (ALP) and cyclooxygenase-2 (COX2) were differentially expressed. Apoptosis was not observed, together indicating that osteogenic calcification took place. Interestingly, both OSM and PI were able to induce calcification in vitro, revealing in vitro-ex vivo differences. In addition to the calcification in the aortic valves, endochondral calcification was present in the sinus near the hinge of the aortic valve in both PI and OSM conditions as evidenced by the expression of collagen II, aggrecan and ALP.

Conclusions
Together these data show that we have established an ex vivo calcification model for mouse aortic valves. Osteogenic calcification is induced in the aortic leaflets, whereas endochondral calcification is induced in the aortic sinus, reflecting the calcification found in human CAVD. Using this model, we can now study the initiation and progression of aortic valve calcification.

Funding Acknowledgement
Type of funding source: Other. Main funding source(s): Dutch Heart Foundation, grant number 2013T093. Grants received from GE Healthcare, Lantheus medical imaging, St Jude Medical, Medtronic, Boston Scientific, Biotronik, and Edwards Lifesciences
Toll-like-receptor-3 function is critical for aortic valve stenosis development in mice
Authors: Niepmann S.T , Boucher A.S , Bulic M , Goody P.R , Jansen F , Treede H , Nickenig G , Zimmer S 
Published: November 2020

Abstract

Background
Aortic valve stenosis (AS) is the most common valve diseases in the western world. After having been considered a passive degenerative process, which develops as an inevitable consequence of age-related valvular degeneration, basic research of the last two decades has led to a paradigm shift. It is now believed that AS pathophysiology is driven by distinct molecular and cellular mechanisms which include inflammatory pathways. In recent years, Toll-like-receptor-3 (TLR3) has emerged as a major regulator of vascular inflammation. TLR3 is a lysosomal pattern recognition receptor that recognizes single and double stranded RNA. Its activation leads to expression of pro-inflammatory cytokines via NFkb activation. The role of TLR3 in the development of AS has never been investigated.

Methods
Severe AS was induced in Wildtype-, ApoE- and TLR3/ApoE−/− mice. For this, a coronary springwire was used to induce an endothelial injury under echocardiographic guidance. Stenosis development was confirmed via ultrasound examinations. To inhibit TLR-3 activation, TLR3/RNA- Complex inhibitor C4a was injected every 48h after wire injury in WT mice. Valves were explanted and stained with hematoxylin/eosin (valve thickening) or anti-68 (macrophage infiltration). Valves from patients who received aortic valve replacement due to AS or aortic regurgitation (AR) were collected and mRNA levels of TLR3 and MyD88 were measured with use of quantitative-PCR.

Results
To evaluate weather TLR3 effects AS development in mice, we subjected TLR3/ApoE double- and ApoE knockout mice to our model of wire-induced AS. Surprisingly, TLR3 deficient mice failed to develop AS after wire injury. Peak velocity measurements showed no increase and histological analysis showed lower aortic valve area and macrophage infiltration compared to control mice. In order to pharmacological inhibit TLR3, WT mice were treated with C4a after wire injury. Compared to PBS control, C4a mice also did not develop AS upon wire injury. Trans-aortic valve peak velocity levels were significantly lower in C4a mice. Histological analysis underlined these results and showed thinner aortic valves and decreased macrophage infiltration in C4a mice comparted to control animals. To confirm our hypothesis, the expression of TLR3 and its downstream effector MyD88 were measured in human aortic valve specimens. qPCR analysis revealed decreased TLR3 and MyD88 expression in patients with AS compared to patients with AR.

Conclusion
In the presented study, we present first data that theTLR3 has a crucial role in the development of AS in mice. The exact downstream effects after TLR3 activation in AS need to be further investigated.

Funding Acknowledgement
Type of funding source: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)