bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dysbiotic microbiome induce cardiac impairment by attenuating brain-derived neurotrophic factor in inflammatory bowel diseases
Authors: Li Q , Zhong X S , Krishnachaitanya S S , Liu M , Ou R , Xiao Y , Powell D W , Fujise K 
Published: November 2023

Abstract

Background & Aims
Mounting evidence suggests that inflammatory bowel disease (IBD) is associated with increased incidences of cardiovascular diseases (CVD), including myocardial infarction and heart failure. However, the molecular mechanisms by which IBD predisposes patients to CVD are poorly understood. This study aimed to identify the role of dysbiosis in gut-heart crosstalk.

Methods
Chronic colitis-induced cardiac impairment was assessed in mice subjected to dextran sodium sulfate (DSS), rats treated with trinitrobenzenesulfonic acid, and IL10-/-mice which develop spontaneous colitis after weaning. Fecal microbiota of wild type or IL10-/- mice were transplanted to C57BL/6J mice treated with microbiome-depleting antibiotic cocktail and germ-free mice to determine if dysbiosis afflicts the heart. Heart function was evaluated by echocardiography. Heart transcriptomes were profiled by RNA-sequencing. Gut microbiota profiling was performed by 16S rRNA sequencing. Adverse effect of brain-derived neutrophic factor (BDNF) deficiency on the heart was evaluated in cardiac-specific BDNF knockout mice (BdnfΔheart).

Results
Impairment of heart function, evidenced by decreased left ventricle ejection fraction (LVEF), increased LV mass, and elevated serum B-type natriuretic peptide, was observed in all 3 models of colitis, providing direct evidence that chronic colitis deteriorates the heart (Figure 1). RNA-sequencing revealed loss of Bdnf and alterations of multiple genes critical to heart homeostasis in the myocardium. Many of the changes, including Bdnf reduction, were found in microbiota-depleted C57BL/6J mice and germ-free mice received dysbiotic fecal microbiome, compared to controls, suggesting that dysbiosis impaired the heart by suppressing Bdnf. BdnfΔheart mice had impaired heart function, including decreased contractility and EF, increased fibrosis, and impaired coronary microcirculation (lower CD31), compared to Bdnf[2lox] mice. Mechanistically, miR-155 in the heart and exosomal miR-29b in the plasma were significantly elevated by chronic colitis. miR-155 and miR-29b mimics suppressed BDNF in cardiomyocytes both in vitro and in vivo. Administration of miR-155 inhibitors or exosomes packaged with miR-29b antagonists ameliorated BDNF reduction in the heart of IL10-/- mice. BDNF supplementation markedly improved heart function in DSS mice.

Conclusions
Chronic colitis impairs the heart through dysbiosis/miR-29b/miR-155/BDNF signaling axis. Targeting this pathway is a promising strategy to overcome gut dysbiosis harmful for the heart in IBD.
Identification of cell-intrinsic effects of mutated circulating cells due to clonal hematopoiesis in patients with heart failure
Authors: Abplanalp W , Schuhmacher B , Cremer S , Merten M , Macinkovic I , Shumliakivska M , Zeiher A M , John D , Dimmeler S 
Published: November 2023

Abstract

Clonal hematopoiesis of indeterminate potential (CHIP) is caused by somatic mutations in hematopoietic stem cells and is associated with worse prognosis in patients with heart failure with reduced ejection fraction (HFrEF). Circulating immune cells derived from patients with HFrEF harboring CHIP mutations show enhanced proinflammatory signatures. However, it is unclear, whether these signatures are derived from the relatively low number of cells harboring CHIP-driver mutations, or are indicators of a systemic pro-inflammatory activation associated with CHIP.

Methods and Results
We assessed the cell-intrinsic effects of the most prevalent CHIP-driver gene (DNMT3A) mutant-carrying circulating immune cells in a total of 5 patients with HFrEF. Using an improved protocol to detect mutant cells on a single cell level (MutDetect-Seq), as illustrated in figure 1A, we show that CHIP mutations can be detected in all major immune cell types (e.g. T cells, monocytes, B cells, NK cells). DNMT3A mutant monocytes demonstrated the highest number of significantly upregulated genes relative to other cell types. Specifically, DNMT3A mutant monocytes exhibit altered gene expression profiles associated with inflammation and phagolysosome function (figure 1B). In addition, DNMT3A mutant carrying CD4+, but not CD8+ T cells, showed significant changes in gene expression patterns towards effector cells and away from a naïve T cell state. Finally, increased paracrine signaling pathways involved in amplifying inflammatory circuits are predicted between mutated and non-mutated monocytes.

Conclusion
This is the first study to decipher the genetic signature of DNMT3A-CHIP-driver mutation carrying circulating immune cells, thereby providing first evidence for the cell intrinsic effects of DNMT3A mutations on peripheral blood cell subsets in patients with HFrEF. The altered gene expression profiles associated with inflammation and phagolysosome function of mutant monocyte as well as the skewing of mutated T cells towards effector cells provide novel insights into how CHIP might promote worse prognosis in heart failure patients.MutDetect-seq
Hematopoietic loss of Y-chromosome in monocytes from heart failure patients associates with cardiac fibrosis signaling
Authors: Abplanalp W , Cremer S , John D , Merten M , Schuhmacher B , Macinkovic I , Dimmeler S , Zeiher A M 
Published: November 2023

Abstract

Background
Hematopoietic mosaic loss of Y chromosome (LOY) increases with age and associates with increased cardiovascular disease incidence. Furthermore, recent murine studies suggest that LOY could potentially promote cardiac fibrosis by stimulating the infiltration and activation of bone marrow-derived macrophages. Yet, specific signatures of hematopoietic LOY cells in patients with heart failure (HF) are missing.

Methods and results
To decode the genetic signature of circulating hematopoietic cells and assess the effects of LOY in human leukocytes, we performed single-cell RNA-sequencing (scRNA-seq) of immune cells from 10 male patients with chronic HF (mean age 67.3 years, ejection fraction 34.4%). We sorted immune cells by presence or absence of Y-chromosome-associated genes (figure 1A). Relative distribution of LOY was assessed, with monocytes having the greatest absolute count of LOY cells with no significant change in distribution among cell types. Given the abundance of monocytic LOY cells we investigated LOY monocytic cells transcriptional signatures (29810 Y-carrier monocytes, 2205 LOY monocytes) in an unbiased manner. Using a patient-specific, paired analysis, LOY monocytes showed significantly reduced expression of TGF-ß inhibiting genes (SMAD7, TGIF2) in LOY cells versus Y-carrier cells. Opposingly, from 193 upregulated genes, LOY cells showed elevated markers associated with monocyte/macrophage-mediated tissue damage and pro-fibrotic cardiac remodelling (S100A8, CLEC4D, TLR2). Gene ontology terms derived from upregulated genes in LOY cells further supported a mechanistic link to cardiac fibrosis by calling terms associated with TLR signaling, which are known to enhance cardiac fibrosis. (figure 1B).

Conclusion
This is the first study to decipher the genetic signature of LOY monocytes in HF patients. Our results considerably extend very recent experimental findings in mice that LOY sensitizes macrophages to enhanced profibrotic signaling. Diminished TGF-ß inhibitory molecules and enhanced TLR signaling may contribute to the aggravation of heart failure by LOY in patients with HF.HF mLOY scRNA-seq
Non-neuronal acetylcholine is causal for cardioprotection by hypoxic preconditioning in adult rat cardiomyocytes
Authors: Braczko F , Reinders J , Lieder H R , Heusch G , Kleinbongard P 
Published: November 2023

Abstract

Introduction
Brief episodes of non-lethal myocardial ischemia/reperfusion preceding more sustained ischemia and reperfusion reduce lethal ischemia/reperfusion injury. The underlying protective signaling mechanisms of such ischemic preconditioning are unclear in their details. Among other protective mediators, neuronal acetylcholine (ACh) and its signaling through cholinergic receptors is involved in protection by ischemic preconditioning. Recently, a non-neuronal cardiac cholinergic system (NNCCS) has been identified, suggesting that a nervous system-independent, cardiomyocyte-derived acetylcholine signaling with signal amplification by auto- and paracrine cholinergic receptor activation could also participate in ischemic preconditioning.

Aim
We aimed to examine the role of NNCCS-derived ACh as a mediator of ischemic preconditioning. We therefore, in a reductionist approach, used isolated adult cardiomyocytes with hypoxic preconditioning (HPC).

Methods
Adult ventricular rat cardiomyocytes were isolated (from n=9 hearts), and HPC was induced by one cycle of 10 min hypoxia / 20 min reoxygenation. Thirty min normoxia served as control. Cardiomyocytes were then exposed to 30 min sustained hypoxia / 5 min reoxygenation (H/R), or a 35 min time control (TC). Cardiomyocyte viability was quantified before and after H/R or TC, respectively, by trypan blue staining. In a subgroup of experiments (cardiomyocytes from n=6 hearts) in the presence of physostigmine (0.2 mmol/L), intracellular ACh was quantified before and after HPC or normoxia and after sustained hypoxia and reoxygenation or TC, respectively, via liquid chromatography-coupled tandem mass spectrometry. Experiments on cardiomyocyte viability (from n=9 hearts) were repeated with the addition of cholinergic receptor antagonists (nicotinic: hexamethonium [1 µmol/L], muscarinic: atropine [0.1 µmol/L]) a) during the first 30 min with HPC or normoxia, b) during H/R or TC (30-65 min), or c) throughout the total 65 min protocol.

Results
The viability of cardiomyocytes subjected to H/R was better preserved with HPC than without (Figure A), and intracellular ACh was increased during hypoxia after prior HPC (Figure B). Cholinergic receptor antagonists during HPC did not change HPC´s protection (Figure A). However, the combination of both antagonists during sustained hypoxia abrogated HPC´s protection (Figure A), whereas nicotinic or muscarinic cholinergic receptor antagonists alone did not. Cholinergic receptor antagonists throughout the total 65 min also abrogated HPC´s protection (Figure A). Conclusion: The NNCCS is activated by HPC and causal for HPC´s protection. HPC increases intracellular acetylcholine, and cardiomyocyte protection is mediated via both nicotinic and muscarinic cholinergic receptors, suggesting an auto- and paracrine signal amplification on the cardiomyocyte level.Figure
Methotrexate associated with nanoparticles decreases NLRC4 inflammasome expression in infarcted rat hearts
Authors: Gatto M , Mota G A F , Borim P A , Santos A C C , Pagan L U , Souza L M , Rodrigues E A , Silva R C F , Oliveira J P G , Meirelles A L B , Brosler J Y , Maranhao R C , Zornoff L A M , Okoshi K , Okoshi M P 
Published: November 2023

Abstract

Abstract: Following myocardial infarction (MI), molecules released from necrotic myocytes sensitize nucleotide-binding receptors (NLRs), activate inflammasome complex, and initiate acute inflammatory process and interleukin (IL)-1β production, essential for tissue damage resolution. However, excessive IL-1β production impairs cardiac remodeling. After MI, IL-1β is released by the NLRP3 inflammasome; involvement of the NLRC4 inflammasome in post-MI remodeling has not been established. Methotrexate (MTX) carried by lipid core nanoparticles in low density emulsion (MTX-LDE) reduces post-MI inflammatory process and improves cardiac function in rodents.

Purpose
To evaluate the influence of early treatment with MTX-LDE on myocardial expression of NLRP3 and NLRC4 inflammasomes in infarcted rats.

Methods
Male Wistar rats were divided into three groups: control (Sham, n=6); MI (n=6); and MI treated with MTX-LDE (MI-MTX, n=6). MI was induced by ligation of the left anterior descending coronary artery. Twenty-four hours later, the MI-MTX group was treated with 1 mg/kg of MTX-LDE, intraperitoneally. Euthanasia was performed 72 hours after surgery under anaesthesia with ketamine and xylazine. Infarct size was assessed by histology. Myocardial expression of NLRC4, NLRP3, ASC, pro-caspase-1, caspase-1, pro-IL-1β and IL-1β was quantified by Western blotting. IL-1β concentration in serum and heart macerate supernatant was analyzed by ELISA. Statistical: ANOVA or Kruskal-Wallis; 5% significance level.

Results
Rats with MI lower than 30% of the left ventricle total area were excluded. Infarct size was larger in the MI-MTX group (43,8 ± 5,4) than MI (36,2 ± 6,22). NLRC4 and caspase-1 expression and IL-1β serum concentration were higher in MI than Sham and MI-MTX. Myocardial IL-1β concentration was higher in MI and MI-MTX than Sham and lower in MI-MTX than MI. NLRP3, ASC, pro-caspase-1, and IL-1β protein expression did not differ between groups.

Conclusion
Our study shows for the first time that NLRC4 inflammasome protein expression increases acutely after myocardial infarction in rats. Early treatment with nanoparticles-derived methotrexate reduces myocardial NLRC4 inflammasome expression and myocardial and serum IL-1β concentration.
Conditional knock out of cytosolic thioredoxin (Trx) in cardiomyocytes impairs cardiac function and exacerbates ischemia-reperfusion injury
Authors: Das K , Kumar S , Fnu K , Shurmur S 
Published: November 2023

Abstract

Introduction
Coronary heart disease with myocardial infarction (MI) is a leading cause of mortality in the world despite timely reperfusion of occluded coronary artery. Myocardial damage due to restoration of blood flow, known as reperfusion injury account for about 50% of final MI size. The role of Trx in protection against myocardial ischemia reperfusion has been reported; however, these studies were mostly performed using ex vivo isolated mouse/rat heart with retrograde perfusion or with injected rhTrx. However, the role of loss of Trx specifically in the myocytes using a conditional deletion has never been reported. Here, we determined whether loss of Trx in myocytes would promote ischemia-reperfusion injury, even if the endocardial endothelial cells express normal levels of Trx.

Purpose
We investigated the effect of specific deletion of Trx in cardiomyocytes on base-line cardiac function and cardiac function in ischemia-reperfusion of heart using conditional knockout of Trx (aMHC-Trx-KO) in the cardiomyocytes with normal levels of Trx in the endothelial cells to determine specifc contribution of Trx in cardiac function in I/R.

Methods
A Trx floxed mouse line was created with introduction of loxP sites flanking the mouse Trx gene. Further, the conditional deletion of Trx in cardiomyocytes was produced by breeding homozygous Trx-floxed (Trxfl/fl) mice with aMHC-Cre mice strain. The resulting aMHC-Trx-KO mice was identified by genotyping and conditional deletion of Trx in myocytes was achieved by injecting Tomoxifen (75mg/Kg in oil). The aMHC-Trx-KO mice were subjected to 30 minutes of ischemia by ligation of left descending coronary artery(LAD) and reperfusion was performed by release of slipknot and allowing blood flow of 60 minutes before sacrificing animals. The animal protocol was approved by the IACUC of the Texas Tech University Health Sciences Center, Lubbock. Echocardiography on animals was performed using Vevo 3100 (Visual Sonic). Statistical analysis was performed by Prism 8.0 (GraphPad).

Results
Deletion of Trx caused significant cardiac dysfunction in aMHC-Trx-KO mice compared to Trxfl/fl mice without treatment with tomoxifen. The ejection fraction (EF%, 52.82 vs. 73.83) and fractional shortening (FS%, 41.42 vs.25.89) were significantly reduced. Further, these mice subjected to I/R showed exacerbated cardiac dysfunction with significant decrease in heart rate and did not survive the reperfusion. We also found significant mitochondrial structural abnormalities and mitochondrial dysfunction in aMHC-Trx-KO mice compared to non-transgenic or Trxfl/fl mice without tomoxifen treatment.

Conclusion
Deletion of Trx in cardiomyocyte causes significant myocardial dysfunction. Further, Trx is required to protect against myocardial dysfunction in ischemia-reperfusion injury. Our data also suggest that cardiac mitochondria is specifically impacted by loss of Trx deletion.Figure-1
Adssl1-mediated purine synthesis modulates cardiomyocyte proliferation and heart regeneration
Authors: Li Z , Zhang R Y , Yan X X 
Published: November 2023

Abstract

Introduction
The enhancement of pre-exist cardiomyocyte proliferation has been proved to be an effective treatment of myocardial infarction(MI) (1-2). Purine bases from the de novo purine synthesis (DNPS) pathways is the critical source of nucleotide synthesis for proliferative cell (3). The muscle specific isoform of adenylosuccinate synthase (Adssl1) catalyses the last step of DNPS pathway (4). Patients with Adssl1 mutation develop cardiomyopathy at 13-15 years (5). Nevertheless, its role and mechanism in cardiomyocyte cell-cycle re-entry and heart regeneration remain unknown.

Purpose
To explore the effect and underlying mechanism of Adssl1 and its mediated DNPS pathway in cardiomyocyte proliferation and heart regeneration.

Methods
We used qRT-PCR, Western blot and Immunofluorescence to assess the expression of Adssl1 during heart developement and heart regeneration after apical resection (AR) operation. Using newly generated loss- and gain-of-function genetic tools to investigate the role of Adssl1 in cardiac regeneration after AR or MI operation. Transcriptomic RNA sequencing (RNA-Seq) and liquid chromatography-tandem mass spectrometry (LC/MS) allowed us to determine the metabolism of Adssl1 in modulating cardiomyocyte proliferation.

Results
Here, we found that Adssl1 was increased during heart regeneration. Depletion of Adssl1 in neonatal hearts significantly inhibited purine synthesis pathway and attenuated heart regenerative capacity after AR operation. Cardiomyocyte-specific overexpression of Adssl1 extended postnatal regenerative window and induced a robust cell-cycle re-entry after MI, leading to a decrease in fibrosis scar size and improvement of cardiac function. Adssl1 caused accumulation of Inosine, which could promote the cardiac repair in mice. Mechanistically, we demonstrated that Adssl1 significantly involved in modulating mTORC1/S6K pathway.

Conclusion
Collectively, our study elucidates the role of Adssl1 in modulating cardiac proliferation and heart regeneration through activating mTORC1/S6K pathway after MI. Notably, Inosine has the potential to be employed as an effective agent in regulating cardiac proliferation and myocardial repair.Heart regeneration
Long non-coding RNA SNHG18 epigenetic regulates ferroptosis in acute myocardial infarction
Authors: Chen J , Zhang B F , Liu G , Liu X P , Chen X Z 
Published: November 2023

Abstract

Background
Loss of terminally differentiated cardiomyocytes is a key pathogenic factor for the occurrence of acute myocardial infarction (AMI) and the development of lethal heart failure. LncRNAs have been confirmed to be critical in regulating AMI, besides, recently published studies disclosed that ferroptosis is a new form of programmed cell death that contributes to AMI. However, whether LncRNAs are involved in the regulation of ferroptosis and correlated underlying mechanisms in AMI remains unknown.

Purpose
Our present study is to investigate LncRNA that regulates cardiomyocyte ferroptosis in AMI and uncover the potential mechanisms.

Method
RNA-sequencing and bioinformatical analyses were conducted to identify the candidate LncRNAs for AMI. Adenovirus for LncRNA knockout and overexpression were constructed to alter the SNHG18 expression of cardiomyocytes in vitro. Cardiomyocyte-specific knockout and overexpression mice were also constructed to alter SNHG18 expression in vivo. Ferroptosis characteristic measurement, including glutathione peroxidase 4 (GPX4), Ferritin heavy chain (FTH-1), ptgs2, MDA, ROS, Fe2+, glutathione, and mitochondrial morphology, was performed to verify the ability of SNHG18 to regulate the ferroptosis of cardiomyocytes. Cardiac morphological, structural, functional, and hemodynamic changes as well as the viability of cardiomyocytes were also measured to assess the effect of SNHG18 on AMI. RNA-pulldown+Mass spectrometry, RNA immunoprecipitation were performed to identify the specific binding factors of SNHG18.

Results
RNA-sequencing results revealed the expression of SNHG18 was significantly and persistently elevated from 3 to 7 days after AMI. SNHG18 was mainly enriched in the nucleus of cardiomyocytes. Besides, the down-regulation of SNHG18 could specifically alleviate the cell viability loss caused by ferroptosis inducers. Thereafter, gain- and loss-of-function experiments were performed both in vitro and in vivo. Functionally, SNHG18 knockout dramatically enhanced cardiomyocyte vitality, reduced infarct size, improved cardiac performance and alleviated cardiac fibrosis by mitigating cardiomyocyte ferroptosis. However, enforced SNHG18 expression resulted in the opposite effects. Mechanistically, the subunit RBBP4 that forms the PRC2 (Polycomb Repressive Complex 2) complex was a direct target of SNHG18, which was also confirmed by RIP assays. In addition, Chip-PCR analysis also demonstrated that PRC2 could directly bind to the promoter region of the GPX4 and FTH1 gene, thus altering the level of H3K27me3 and inhibiting their transcription. Moreover, subsequent rescue experiments further verified that SNHG18 regulated the expression of GPX4 and FTH1 to ameliorate AMI-induced cardiomyocyte ferroptosis in a PRC2-dependent manner.

Conclusion
This study demonstrates that SNHG18-PRC2-GPX4/FTH1 pathway is a promising therapeutic target for the treatment of AMI by ameliorating cardiomyocyte ferroptosis.