bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rimeporide, a first in class Na/H exchanger-1 inhibitor, ameliorates right ventricular dysfunction and pulmonary arterial hypertension in a SuHx model
Authors: Milano G , Reinero M , Sameere A , Porte-Thome F , Beghetti M 
Published: November 2023

Abstract

Background
Pulmonary arterial hypertension (PAH) is characterized by pulmonary vasoconstriction and vascular remodeling leading to right ventricular (RV) failure. Although RV function is the major prognostic factor in PAH, no RV-specific therapies exist. The Na+/H+ exchanger type 1 (NHE1) regulates the intra- and extracellular pH balance mainly through the 1:1 exchange of intracellular H+ with extracellular Na+. Increased NHE-1 activity is involved in several diseases, including hypoxic PAH. Inhibition of NHE-1 activity attenuates pulmonary vascular remodeling in rodents exposed to hypoxia but its potential direct contribution in RV remodeling remains unclear.

Aim
In the current study, we aimed to investigate the effect of NHE-1 inhibition by Rimeporide a preclinical hypoxic models of PH: Sugen5416/hypoxia.

Methods
Sugen/hypoxia model: PAH was induced in adult Sprague-Dawley rats with a single injection of SU5416 (20 mg/kg) followed by 3 weeks of hypoxia (10% O2; Sugen/Hypoxia model: SuHx) and then return to normoxia. Control rats were injected with equal volume of vehicle. At week 5 post-injection, control and SuHx rats were treated with rimeporide (100 mg/Kg daily in drinking water, n=10/group) or placebo (n=11/group) for 3 weeks. Echocardiography and blood sampling were performed. RV phenotype was monitored by echocardiography and hemodynamic analysis. Lung and heart were collected for histological and protein expression analysis, such as NHE-1 (target of Rimeporide).

Results
SuHx caused severe PAH and RV dysfunction. RV dysfunction was accompanied by an increase in RV hypertrophy and RV fibrosis and PA remodeling (increase in the arteriolar wall thickness and fibrosis). A marked increase in macrophages was found in lung and RV tissues but not in LV. Moreover, Western blot analysis showed that RV protein levels of NHE-1 was higher in SuHx rats than Normoxia rats. Treatment with Rimeporide reversed SuHx-induced PAH as well as RV dysfunction and blunted pulmonary and RV inflammation, RV NHE-1 protein expression.

Conclusion
Our results indicate that NHE-1 levels are increased in RV tissues from SuHx-induced PAH rats. Rimeporide, through NHE-1 inhibition, might be a potential new target for treatment of RV dysfunction and PAH.
CaMKIIdelta-mediated SR Ca leak contributes to long-term Doxorubicin-induced cardiotoxicity
Authors: Feder A L , Tarnowski D , Maier L S , Sag C M 
Published: November 2023

Abstract

Background
Cardiotoxicity represents a major complication of cancer therapy with anthracyclines, whose main known compound is doxorubicine (DOX). Although mechanisms of DOX-induced toxic cardiomyopathy (DICM) are not entirely understood, CaMKIIδ-activity is known to be increased upon acute DOX exposure, contributing to impaired Calcium (Ca) handling. However, currently no studies have addressed the question, whether CaMKIIδ is involved in DOX-induced long-term cardiotoxicity.

Purpose
We aimed to investigate cardiac function and intracellular Ca handling using an in-vivo DOX treated mouse model, examining whether CaMKIIδ is involved in DOX-induced long-term cardiotoxicity.

Methods
Cardiac function and excitation-contraction coupling of CaMKIIdWT and CaMKIId-/- (global CaMKIId knockout) mice were tested in an in-vivo DOX treated mouse model (cumulative dose 12 mg/kg, intraperitoneal injection). Cardiac function was determined by echocardiography after 12 weeks. Ca handling of freshly isolated cardiomyocytes was assessed by epifluorescence microscopy (Fura2-AM) and confocal microscopy (Fluo4-AM). Histological analyses regarding cardiac fibrosis and cell dimensions were examined.

Results
Long-term DOX exposure reduced left ventricular ejection fraction (EF) by ∼13% and markedly increased cardiac fibrosis in CaMKIIδWT mice. Moreover, CaMKIIdWT hearts displayed decreased cell volume indicating atrophy following DOX treatment. Coinciding with the reduction in EF, CaMKIIdWT mice showed depressed Ca transient amplitudes as well as slowed Ca transient decay indicating depressed Ca uptake into the sarcoplasmic reticulum (SR). In addition, spontaneous diastolic Ca leakage from the SR was dramatically increased. In contrast, CaMKIId-/- mice showed preserved EF following 12 weeks of DOX treatment as compared to CaMKIIdWT in line with maintained Ca transient amplitudes. As an underlying cause, SR Ca leakage was not increased in CaMKIId-/- myocytes despite DOX-treatment. Pharmacological CaMKII inhibition using AIP (1µM) prevented SR Ca leak and restored Ca transient amplitudes in DOX-treated CaMKIIdWT myocytes.

Conclusion
Our study shows that CaMKIId contributes to long-term DOX-induced cardiotoxicity. We found that chronic DOX treatment induced depressed cardiac function and myocardial fibrosis, associated with impaired calcium handling as a consequence of CaMKIId-mediated SR Ca leak, which was absent in our CaMKIId-/- mouse model. In line, pharmacological inhibition of CaMKII rescued impaired Ca handling in DOX-treated CaMKIIdWT myocytes.
The anti-fibrotic effect of atrial natriuretic peptide depends on myocardial accumulation of the peptide in rat heart
Authors: Hatem S N , Bakhos J J , Saliba Y , Hajal J , Achkouty G , Semaan A , Fares N 
Published: November 2023

Abstract

Background
The atrial natriuretic peptide (ANP) has an anti-fibrotic function for the heart. However, during heart failure (HF), which is characterized by marked myocardial fibrosis, ANP has a time-limited effect due to the rapid peptide degradation. Angiotensin-receptor-neprilysin inhibitors are a new class of drug that inhibits ANP degradation and improves cardiac performance, raising the question of the impact of increased ANP bioavailability on this pharmacological effect.

Purpose
We aim to assess the impact of intracardiac accumulation of ANP on cardiac function and myocardial fibrosis. An original strategy consisted of using a mutated ANP, MANP, also known as fsANP (frameshift), which is highly resistant to enzymatic degradation.

Methods
Type 2 diabetes was induced in adult male rats by a high fat diet coupled to low dose streptozotocin injections (25 mg/kg). MANP and ANP were administered each at a dose of 2 pmol/kg/min by subcutaneous osmotic minipumps. Sacubitril was given orally at a dose of 18 mg/kg. The protocol duration was 42 days. Cardiac fibrosis and cultured cardiac fibroblasts (CFs) were evaluated in the presence or absence of ANP, MANP, and angiotensin-receptor-neprilysin inhibitors; sacubitril. In addition to classical immunohistological and biochemical approaches, cGMP production was measured by real-time imaging in live cultured CFs (n=477). Results: MANP and sacubitril preserved cardiac performance more efficiently than ANP (p&lt;0.05). Moreover, MANP, as well as sacubitril attenuated myocardial, epicardial, and perivascular fibrosis were more efficient than ANP (p&lt;0.05). There was an increase in the bioavailability of MANP compared to ANP in cardiac tissue (p&lt;0.05). Furthermore, a high-level expression of protein kinase G, and inhibition of the SMADs signaling pathway were identified in CFs. Moreover, cGMP bio-sensing in CFs, showed that similarly to ANP, MANP enhances cGMP production and activates PKG signaling, resulting in similar SMADs pathway inhibition (p&lt;0.05). These results indicate similar biological efficiency as ANP and MANP.

Conclusion
MANP and sacubitril are more efficient than ANP to improve cardiac function and to reduce myocardial fibrosis in HF. Both molecules increase ANP bioavailability. This study proves that tissue accumulation of ANP is an important therapeutic target during HF.
Effects of pericyte and smooth muscle specific knock-out of CXCL12 on cardiac function after myocardial ischemia in mice
Authors: Staggl S , Messner M , Seiringer H , Ghadge S K , Maurer T , Poelzl G , Bauer A , Zaruba M M 
Published: November 2023

Abstract

Introduction
Ischemic cardiomyopathy as a result of myocardial infarction represents one of the most common causes of heart failure (1). The C-X-C motif chemokine ligand 12 (CXCL12) and its receptor CXCR4 facilitate cardiac repair after myocardial ischemia (MI) and play fundamental roles in cardiovascular development (2). However, the cell- and tissue-specific actions of CXCL12 are poorly understood, limiting the introduction of targeted therapies. Here, we aimed to examine the role of pericyte and smooth muscle cell-specific CXCL12 expression on myocardial function after MI.

Methods
We generated a smooth muscle protein 22-alpha-Cre and a pericyte protein NG2-Cre driven mouse model to ablate CXCL12 specifically in smooth muscle cells (SM22-Cre x CXCL12flox/flox) and in pericytes (NG2-Cre x CXCL12flox/flox). Genotyping was performed using ear hole biopsy by PCR. Hearts were analysed morphologically by histology and immunofluorescence. Cardiac function and dimensions of the wall thicknesses and cardiac cavities were determined by echocardiography. Myocardial infarction was induced in the animals and cardiac function was further investigated 28 days after MI.

Results
In immunofluorescence, we found that CXCL12 is highly expressed in SM22+ smooth muscle cells and in cells surrounding arterial blood vessels (3). NG2-CXCL12-/- mice did not show increased mortality, they behaved inconspicuously and no obvious developmental defects could be detected. Echocardiographic analysis of cardiac function in NG2-Cre x CXCL12flox/flox mice without infarction showed no significant difference in left ventricular (LV) performance and no evidence of abnormal geometry of the ventricles compared with controls. Assessment of SM22-Cre x CXCL12flox/flox mice after MI revealed reduced ejection fraction (EF) (29.0%±9.7 vs. 40.0%±8.1; n=10; p=0.027) and stroke volume (SV) (19.0µl±3.3 vs. 32.7µl±10.3; n=10; p=0.002) compared to non-transgenic controls. In contrast NG2-Cre x CXCL12flox/flox mice showed no significant changes in EF (34.6%±11.4 vs. 40.0%±8.1; n=10; p=0.368) and SV (27.7µl±7.3 vs. 32.7µl±10.3; n=10; p=0.303).

Conclusion
Our findings suggest that pericyte specific CXCL12 plays no major role in cardiac development and function after MI. In contrast, KO of CXCL12 in smooth muscle seems to deteriorate cardiac function after ischemia.
Protein tyrosine phosphatase sigma and zeta1 regulate cardiac fibroblast contractile function through TGF-beta dependent and independent pathways
Authors: Weidner J , Faist D , Irengbam R , Theilmeier G , Hasselbach L 
Published: November 2023

Abstract

Background
Heart failure is a frequently fatal cardiovascular disease with limited therapeutic options. To improve our understanding of signaling pathways in affected cells is therefore important. Protein tyrosine phosphatase sigma (PTPRσ) and zeta 1 (PTPRz1) have been shown to be involved in cardiac development and disease [1,2].
Both phosphatases are upregulated in patients with end stage heart failure. We demonstrated that PTPRz1 inhibits while PTPRσ is required for migration of neonatal cardiac fibroblasts (nCF) [3].

Purpose
To further evaluate the influence of PTPRσ and PTPRz1 on fibroblast phenotype with regard to stress fiber formation and collagen contraction and their interaction with the TGFβ pathway.

Methods
nCF were transfected with either scrambled-, PTPRσ-, PTPRz1-, or both siRNAs. mRNA lysates were harvested 24h after transfection with subsequent rt-PCR analysis for the phosphatases. Transfected cells were seeded and stained with labeled phalloidin to measure the formation of stress fibers or in collagen gel matrices to evaluate their contractile capacities. To evaluate the nuclear translocation of SMAD3 immunohistochemical colocalization of SMAD3 and DAPI was quantified. Data were analyzed by Kruskal-Wallis and Mann-Whitney-U or ANOVA followed by t-test with Welsh correction using GraphPad prism.

Results
PTPRz1 and -σ knockdown (kd) was highly efficient (&gt;85%). PTPRz1 mRNA was upregulated by 48% after PTPRσ kd (p &lt; 0.05, n=4) but not vice versa and not after combined kd. Compared to control, nCF showed a 26% increase in the number of stress fibers in response to the PTPRz1 kd (p = 0.057, n=3-4) and an increase of 29% after PTPRσ/-z1 kd (p &lt; 0.05, n=4). Collagen gels were contracted to about 70% of their surface by TGFβ in control (p&lt;0.05, n=4) or any kd condition. They were also contracted by 24,5% after PTPRz1 knockdown (p &lt; 0.01, n=4), whereas the additional kd of PTPRσ obliterated the effect. Nuclear translocation of SMAD3 was roughly doubled upon TGFβ stimulation in controls and all kd conditions. In unstimulated nCF, PTPRσ kd induced a 28%, PTPRz1 kd a 45%, and their combination a 114% increase of nuclei positive for SMAD3 (p &lt; 0.05).

Conclusion
SMAD3 nuclear translocation is additively induced by PTPRz1 and PTPRσ kd independent of TGFβ. Stress fiber formation, however, seems to be inhibited by PTPRz1 independent of PTPRσ, while PTPRz1-kd-induced collagen contraction does depend on the presence of PTPRσ. PTPRσ and PTPRz1 thus have separate, overlapping and antagonistic effects that are TGFβ dependent and independent. The elucidation of the involvement of the phosphatases in fibroblast signaling and function could improve our understanding of adverse remodeling during heart failure and deliver novel options for therapeutic interventions.
Interleukin-22 deficiency exacerbates right ventricular remodeling during pressure overload
Authors: Shibao K , Yasukawa H , Akagaki D , Okabe K , Yanai T , Shima K , Ymamoto M , Fukumoto Y 
Published: November 2023

Abstract

Background
Fibrosis and remodeling of right ventricle (RV) are associated with prognosis in patients with RV failure. Interleukin-22 (IL-22) is a member of the IL-10 cytokine family, play roles in tissue protection and wound repair. We have previously shown that IL-22 plays an important role in cardiac remodeling after acute myocardial infarction; however, the role of IL-22 in RV fibrosis and remodeling remains elusive.

Purpose
We investigated the role of IL-22 in the pathogenesis of RV remodeling during pressure overload.

Methods
Pulmonary artery banding (PAB) is performed by placing a 6-0 suture around the pulmonary artery over a 24 G needle in wild type mice (C57BL/6J) and IL-22 knockout mice (IL-22 KO). Only mice with moderate pulmonary artery stenosis (peak pressure gradient across the pulmonary band: 25–40 mmHg at 1 week after surgery by echo Doppler) were included in the study protocol. Two weeks after PAB, RV function was measured by echocardiography and real-time PCR analysis was performed to measure IL-22, IL-22 receptor subunit alpha 1 (IL-22RA1), and IL-22 signaling inhibitor IL-22 binding protein (IL-22BP).

Results
2 weeks after PAB, IL-22 KO mice showed markedly increased RV weight (IL-22 KO mice vs. wild-type mice; RV/LV+IVS: 0.48±0.05 vs 0.40±0.02, P=0.002). IL-22 KO mice exhibited significant RV enlargement and RV dysfunction 2 weeks after PAB. (IL-22 KO mice vs wild type mice; RVEDV: 10±2.3mm2 vs 12.9±3.1mm2, P=0.005, TAPSE: 10.8±1.8mm vs 9.5±1.7mm, P=0.04, FAC: 35.2±7.8% vs 23±6.0%, P&lt;0.001). The expression of IL-22, IL-22RA1 and IL-22BP in the RV tended to increase 2 weeks after PAB (wild-type mice with PAB (n=3) vs. wild-type mice with sham; IL-22: 0.0023 vs 0.0028, P=0.18 IL-22RA1: 1.489 vs 1.773, P=0.175, IL-22BP: 0.025 vs 0.067, p=0.005).

Conclusion
These results suggest that IL-22 is involved in RV remodeling during RV pressure overload.
Population-specific and cross-ancestry genome-wide association study identifies shared genetic architecture and 6 new risk loci including CAMK2D associated for Brugada syndrome
Authors: Makita N , Ishikawa T , Masuda T , Hachiya T , Dina C , Simonet F , Tank M W T , Wilde A A , Redon R , Bezzina C R , Tanaka T , Barc J , Okada Y , Schott J J 
Published: November 2023

Abstract

Introduction
The Brugada syndrome (BrS) is an inherited arrhythmia characterized by coved-type ST-segment elevation in the right precordial leads and an increased risk for sudden cardiac death. Genome-wide association studies (GWAS) of BrS, mainly performed in European ancestry, have illustrated its complex genetic architecture as an polygenic disease besides a monogenic trait due to mutations in the major responsible cardiac sodium channel gene SCN5A. Clinical manifestations of BrS including the disease prevalence and the incidence of sudden death are known to be variable between Asian and European populations, however, its underlying mechanisms are largely unknown.

Objectives
We aimed to identify novel BrS-associated loci and to assess ancestry-dependent genetic heterogeneity that may underlie the variable clinical manifestations of BrS patients across different populations.

Methods
We performed a genome-wide meta-analysis of BrS in the Japanese ancestry (940 cases and 1,634 controls), followed by a cross-ancestry meta-analysis of Japanese and European GWAS (total of 3,760 cases and 11,635 controls) to identify novel risk loci and compared the allelic effects between two ancestries. We characterized the novel loci based on fine-mapping of potential causal variants, and expression and splicing quantitative trait associations using the Genotype-Tissue Expression (GTEx) database.

Results
The Japanese-specific genome-wide meta-analysis identified a novel association signal near the ZSCAN20 (lead variant, rs2336244; P=1.0E-08) besides previously reported 4 association signals at the SCN5A-SCN10A and HEY2 loci. Cross-ancestry genome-wide meta-analysis identified 17 association signals including 6 novel loci. The effect directions were consistent for 94.1% of the variants (16 of 17; P for sign test = 0.00027) and their allelic effects were highly correlated across ancestries (Pearson’s R=0.91 [P=2.9E-07]). The genetic risk score (GRS) derived from European-ancestry GWAS of BrS was significantly associated with the risk of BrS in the Japanese populations (odds ratio, 2.12 [95% confidence interval, 1.94–2.31]; P=1.2E-61), suggesting the shared genetic architecture across ancestries. The functional characterization of the 6 novel loci showed that one lead SNP on CAMK2D promotes an alternative splicing resulting in an isoform switch of calmodulin kinase II that favors up-regulation of the pro-inflammatory isoform δ9 and down-regulation of the pro-survival isoform δ3.

Conclusions
Our results identified 6 novel susceptible loci associated with BrS and revealed shared genetic architecture across ancestries.GWAS Manhattan plotShared genetic architecture
In vitro model of atrial fibrillation: investigating the initiation and maintenance mechanisms of atrial remodeling using hiPSC-derived atrial cardiomyocytes
Authors: Casini M , Fambuena Santos C , Emig R , Peyronnet R , Ravens U , Ontoria Oviedo I , Climent A , Sepulveda P 
Published: November 2023

Abstract
Despite atrial fibrillation (AF) being a common, clinically important, and economically significant public health problem, the initiation mechanisms of atrial remodeling during AF is still unclear. Furthermore, really few experimental models have the power to investigate these mechanisms in a human invitro two-dimensional (2D) monolayer of atrial cardiomyocytes.
The purpose of this work is to use human induced pluripotent stem cell (hiPSC)-derived atrial cardiomyocytes to develop a new human in vitro atrial model of AF able to reproduce and evaluate the arrhythmia initiation and maintenance mechanisms.
Two different hiPSC lines were differentiated into atrial cardiomyocytes using 1 µM retinoic acid from day 3 to day 8. Protocol to differentiate atrial cells was compared with the classical method to generate ventricular hiPSC to demonstrate atrial specificity. On day 20 of the differentiation cells were seeded into plates with different sizes: 0.32 cm2 and 9.6 cm2, a larger size that allows rotor formation. After 10 days qPCR and optical mapping experiments were performed at 37˚C. These experiments aimed to evaluate the electrophysiologic and genetic remodeling the
Cells undergo during AF initiation and maintenance.
The atrial phenotype was assessed by patch clamp recordings that showed cells treated with RA had significantly shorter action potential duration at 90% repolarization compared to the no RA treated, 182.3.5 ± 68 ms and 371.6 ± 82 ms, faster depolarization rate and higher spontaneous beating frequency (n=14, ± SD). Optical mapping experiments allowed the evaluation of activation rate depending on the size of the dish: larger wells activated spontaneously at 1.6 ± 1.9 Hz, whereas smaller wells presented 0.9 ± 0.5 Hz of activation rate. The fast activation rate on larger wells was associated higher number of reentrant wavefronts: 11.0 ± 8.2 reentries/cm2, vs 0.9 ± 0.5 reentries/cm2 in the smaller wells, demonstrating an AF phenotype. In fact, depending on the culture conditions cells showed different reentries occurrence: 100% of large dishes exhibited fibrillation compared to only 10% of small dishes. Furthermore, qPCR studies demonstrated that the spontaneous initiation and maintenance of rotors in the larger well sizes lead to an expression remodeling of the channels SCN5A, KCNJ2, GJA5, ATP2A2, and RYR2 as previously demonstrated on isolated tissue from AF patients.
We conclude that atrial cardiomyocytes obtained from hiPSC can recapitulate the remodeling that atrial tissue undergoes during AF initiation in patients. Providing a unique opportunity to study the initiation of fibrillatory activities and their maintenance in a human-relevant in-vitro model.hiPSC-aCM characterizationElectrophysiologic & genetic remodeling