Abstract 17332: Endothelial-Specific Deletion of Aryl Hydrocarbon Receptor Nuclear Translocator (ARNT) Leads to Microvascular Barrier Dysfunction and Cardiomyopathy

Introduction: Cardiac microvascular hyperpermeability is a key contributor to heart disease in patients with diabetes. Although the link between diabetes and microvascular barrier dysfunction is largely unknown, expression of the transcription factor aryl hydrocarbon receptor nuclear translocator (ARNT) is significantly downregulated in the cardiac microvascular endothelial cells (CMECs) of both diabetic mouse hearts (n=5, p<0.01) and the explanted hearts of patients with diabetes mellitus (n=3, p<0.05). We hypothesize that cardiac microvascular permeability is limited by the expression of ARNT in the endothelium and, consequently that endothelial-cell ARNT (ecARNT) expression is essential for normal cardiac function. Methods and Results: We have recently generated tamoxifen-inducible, endothelial-cell-specific, VE-cadherin-Cre ETR2 ARNT-knockout mice (ecARNT -/- mice). ecARNT deletion is achieved by tamoxifen oral administration for two weeks. Littermates controls are either mice without tamoxifen chow or ARNT flox/flox treated with tamoxifen diet. Induction of the ecARNT -/- mutation led to vascular leakage (as determined via in-vivo endothelial permeability assay) (n=5, p<0.05), which occurred predominantly in the heart, and to increases in matrix metalloproteinase (MMP) expression (microarray analysis), including a 3.8-fold increase in the expression of MMP3 (n=3, p<0.01). Furthermore, MMP3 inhibition attenuated the increase in cell permeability observed in CMECs from ecARNT -/- mouse hearts (as measured via electrical cell-substrate impedance sensing), as well as cardiac vascular leakage in ecARNT -/- mice, while long-term studies indicated that ejection fractions were significantly lower (ecARNT -/- : 22.3±2.6%, Control: 33.2±1.8%;), and Left ventricular end-diastolic diameters were significantly greater (ecARNT -/- : 4.8±0.8 mm, Control: 3.6±0.6 mm; n=8,p<0.01) six months after ecARNT deletion (echocardiography). Conclusion: ARNT-mediated MMP3 downregulation is required for maintaining cardiac microvascular barrier integrity and preserving cardiac function; thus, modulation of the ARNT/MMP3 axis could be a novel approach for the treatment of cardiovascular diseases such as diabetic cardiomyopathy.

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Activation of Aryl Hydrocarbon Receptor by ITE Improves Cardiac Function in Mice After Myocardial Infarction

Journal of the American Heart Association ◽

10.1161/jaha.120.020502 ◽

2021 ◽

Author(s):

Eunhwa Seong ◽

Jun‐Ho Lee ◽

Sungmin Lim ◽

Eun‐Hye Park ◽

Eunmin Kim ◽

...

Keyword(s):

Myocardial Infarction ◽

T Cells ◽

Regulatory T Cells ◽

Cardiac Function ◽

Aryl Hydrocarbon Receptor ◽

Inflammatory Responses ◽

Left Ventricular ◽

M2 Macrophage ◽

Aryl Hydrocarbon ◽

Acute Mi

Background The immune and inflammatory responses play a considerable role in left ventricular remodeling after myocardial infarction (MI). Binding of AhR (aryl hydrocarbon receptor) to its ligands modulates immune and inflammatory responses; however, the effects of AhR in the context of MI are unknown. Therefore, we evaluated the potential association between AhR and MI by treating mice with a nontoxic endogenous AhR ligand, ITE (2‐[1’H‐indole‐3’‐carbonyl]‐thiazole‐4‐carboxylic acid methyl ester). We hypothesized that activation of AhR by ITE in MI mice would boost regulatory T‐cell differentiation, modulate macrophage activity, and facilitate infarct healing. Methods and Results Acute MI was induced in C57BL/6 mice by ligation of the left anterior descending coronary artery. Then, the mice were randomized to daily intraperitoneal injection of ITE (200 µg/mouse, n=19) or vehicle (n=16) to examine the therapeutic effects of ITE during the postinfarct healing process. Echocardiographic and histopathological analyses revealed that ITE‐treated mice exhibited significantly improved systolic function ( P <0.001) and reduced infarct size compared with control mice ( P <0.001). In addition, we found that ITE increased regulatory T cells in the mediastinal lymph node, spleen, and infarcted myocardium, and shifted the M1/M2 macrophage balance toward the M2 phenotype in vivo, which plays vital roles in the induction and resolution of inflammation after acute MI. In vitro, ITE expanded the Foxp3 + (forkhead box protein P3‐positive) regulatory T cells and tolerogenic dendritic cell populations. Conclusions Activation of AhR by a nontoxic endogenous ligand, ITE, improves cardiac function after MI. Post‐MI mice treated with ITE have a significantly lower risk of developing advanced left ventricular systolic dysfunction than nontreated mice. Thus, the results imply that ITE has a potential as a stimulator of cardiac repair after MI to prevent heart failure.

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Abstract 314: BRaf Plays a Major Role in Gene Expression in Cardiomyocytes in Mouse Hearts in vivo

Circulation Research ◽

10.1161/res.121.suppl_1.314 ◽

2017 ◽

Vol 121 (suppl_1) ◽

Author(s):

Michelle A Hardyman ◽

Stephen J Fuller ◽

Daniel N Meijles ◽

Kerry A Rostron ◽

Sam J Leonard ◽

...

Keyword(s):

Gene Expression ◽

Cardiac Hypertrophy ◽

Cardiac Function ◽

Left Ventricular ◽

Braf Mutations ◽

Gene Markers ◽

Lv Mass ◽

Cardiac Volumes

Introduction: Raf kinases lie upstream of ERK1/2 with BRaf being the most highly expressed and having the highest basal activity. V600E BRaf mutations constitutively activate ERK1/2 and are common in cancer. The role of BRaf in the adult heart is yet to be established. ERK1/2 regulate cardiomyocyte gene expression, promoting cardiac hypertrophy and cardioprotection, but effects of ERK1/2 may depend on signal strength. Hypothesis: Our hypotheses are that BRaf is critical in regulating ERK1/2 signaling in cardiomyocytes and, whilst moderate ERK1/2 activity is beneficial, excessive ERK1/2 activity is detrimental to the heart. Methods: We generated heterozygote mice for tamoxifen- (Tam-) inducible cardiomyocyte-specific knockin of V600E in the endogenous BRaf gene. Mice (12 wks) received 2 injections of Tam or vehicle on consecutive days (n=4-10 per group). Kinase activities and mRNA expression were assessed by immunoblotting and qPCR. Echocardiography was performed (Vevo2100). M-mode images (short axis view) were analyzed; data for each mouse were normalized to the mean of 2 baseline controls. Results: V600E knockin did not affect overall BRaf or cRaf levels in mouse hearts, but significantly increased ERK1/2 activities within 48 h (1.51±0.05 fold). Concurrently, mRNAs for hypertrophic gene markers including BNP and immediate early genes (IEGs) increased signficantly. At 72 h, expression of BNP, Fosl1, Myc, Ereg and CTGF increased further, other IEGs (Jun, Fos, Egr1, Atf3) declined, and ANF was upregulated. In contrast, expression of α and β myosin heavy chain mRNAs was substantially downregulated (0.46/0.41±0.05 relative to controls). Within 72 h, left ventricular (LV) mass and diastolic LV wall thickness had increased (1.23±0.05 relative to controls), but cardiac function was severely compromised with significant decreases in ejection fraction and cardiac output (0.53/0.68±0.09 relative to controls) associated with increased LV internal diameters and cardiac volumes. Conclusions: Endogenous cardiomyocyte BRaf is sufficient to activate ERK1/2 in mouse hearts and induce cardiac hypertrophy associated with dynamic temporal changes in gene expression. However, excessive activation of ERK1/2 in isolation is detrimental to cardiac function.

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Effect of human urotensin-II infusion on hemodynamics and cardiac function

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y03-004 ◽

2003 ◽

Vol 81 (2) ◽

pp. 125-128 ◽

Cited By ~ 33

Author(s):

Ghada S Hassan ◽

Fazila Chouiali ◽

Takayuki Saito ◽

Fu Hu ◽

Stephen A Douglas ◽

...

Keyword(s):

Cardiac Function ◽

Diastolic Pressure ◽

Cardiac Contractility ◽

Systolic Pressure ◽

Left Ventricular ◽

Urotensin Ii ◽

Ventricular Systolic Pressure ◽

Wide Range ◽

Dose Dependent Decrease

Recent studies have shown that the vasoactive peptide urotensin-II (U-II) exerts a wide range of action on the cardiovascular system of various species. In the present study, we determined the in vivo effects of U-II on basal hemodynamics and cardiac function in the anesthetized intact rat. Intravenous bolus injection of human U-II resulted in a dose-dependent decrease in mean arterial pressure and left ventricular systolic pressure. Cardiac contractility represented by ±dP/dt was decreased after injection of U-II. However, there was no significant change in heart rate or diastolic pressure. The present study suggests that upregulation of myocardial U-II may contribute to impaired myocardial function in disease conditions such as congestive heart failure.Key words: urotensin-II, rat, infusion, heart.

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Oral delivery of xenon for cardiovascular protection

Scientific Reports ◽

10.1038/s41598-019-50515-3 ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Xing Yin ◽

Melanie R. Moody ◽

Valeria Hebert ◽

Melvin E. Klegerman ◽

Yong-Jian Geng ◽

...

Keyword(s):

Cardiac Function ◽

Oral Delivery ◽

Noble Gas ◽

Left Ventricular ◽

Beneficial Effects ◽

Normal Left Ventricular ◽

Term Administration ◽

Apoe Knockout Mice

Abstract Cardiac hypertrophy often causes impairment of cardiac function. Xenon (Xe), a naturally occurring noble gas, is known to provide neurological and myocardial protection without side effects. The conventional method of Xe delivery by inhalation is not feasible on a chronic basis. We have developed an orally deliverable, effective Xe formulation for long-term administration. We employed 2-hydroxypropyl)-β-cyclodextrin (HPCD), which was dissolved in water to increase the Xe concentration in solution. The beneficial effects of long-term oral administration of Xe-enriched solutions on cardiovascular function were evaluated in vivo. HPCD increased Xe solubility from 0.22 mM to 0.67 mM (3.8-fold). Aged ApoE knockout mice fed high-fat diet for 6 weeks developed hypertension, and myocardial hypertrophy with impaired cardiac function. Oral Xe prevented this ischemic damage, preserving normal blood pressure, while maintaining normal left ventricular mass and wall thickness. This novel formulation allows for gastrointestinal delivery and cardiovascular stabilization.

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Abstract 16708: Cathelicidin Related Antimicrobial Peptide Treated Bone Marrow Derived Mononuclear Cells Improves Cardiac Function in a Mouse Model of Acute Myocardial Infarction: Potential Therapeutic Targets in Ischemic Heart Disease

Circulation ◽

10.1161/circ.130.suppl_2.16708 ◽

2014 ◽

Vol 130 (suppl_2) ◽

Author(s):

Yuri M Klyachkin ◽

Prabhakara R Nagareddy ◽

Ahmed Asfour ◽

Shaojing Ye ◽

Erhe Gao ◽

...

Keyword(s):

Heart Disease ◽

Cardiac Function ◽

Ischemic Heart Disease ◽

Infarct Size ◽

Left Ventricular ◽

Ischemic Heart ◽

In Vivo Studies ◽

Boyden Chamber ◽

Acute Ischemic Heart Disease

Introduction: Limited stem cell retention following intracoronary administration for ischemic heart disease has reduced the clinical efficacy of this novel therapy. Cathelicidins have been shown to prime BMMNC migration towards low gradients of SDF-1 suggesting a potential role in BMMNC retention. We sought to assess the safety and efficacy of BMMNC pre-treatment with CRAMP for treatment of acute ischemic heart disease. METHODS: BMMNCs isolated from GFP mice were incubated with recombinant CRAMP (2.5 μg/ml) or placebo for 1 hour followed by chemotaxis studies towards low levels of SDF-1 (2 ng/ml) using a Boyden chamber in vitro. During the in vivo studies, mice were randomized into 3 groups: AMI followed by injection of phosphate buffered saline (PBS), BMMNCs alone, or BMMNCs incubated with CRAMP. Scar size, survival and retention of injected BMNNCs were examined by immunohistochemistry at 5 weeks. Left ventricular function was measured by echocardiography at baseline, 48 hours, and 5 weeks after MI. Changes in infarct size between 5 days and 5 weeks after AMI was assessed by cardiac MRI utilizing delayed gadolinium enhancement. RESULTS: Treatment of BMNNCs with CRAMP enhanced their migration towards low, yet physiological, levels of SDF-1 (Fig 1A). In vivo, a greater proportion of cell survival and retention was observed in the BMNNC+CRAMP group than in the BMNNC-alone group (Fig 1B) and this was associated with higher percentage of BrdU positive cells (Fig 1C). Moreover, BMNNC+CRAMP administration led to significantly better survival, improvement of cardiac function (Fig 1D-H) and reduction in infarct size compared with other control groups (Fig 1I). CONCLUSIONS: Cathelicidins enhance BMMNC retention after intramyocardial administration for acute ischemic heart disease resulting in enhanced recovery. Therapies employing this strategy may represent an effective method for improving cardiac recovery and survival rate after AMI in human studies.

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Increase Paclitaxel Sensitivity to Better Suppress Serous Epithelial Ovarian Cancer via Ablating Androgen Receptor/Aryl Hydrocarbon Receptor-ABCG2 Axis

Cancers ◽

10.3390/cancers11040463 ◽

2019 ◽

Vol 11 (4) ◽

pp. 463 ◽

Cited By ~ 4

Author(s):

Wei-Min Chung ◽

Yen-Ping Ho ◽

Wei-Chun Chang ◽

Yuan-Chang Dai ◽

Lumin Chen ◽

...

Keyword(s):

Ovarian Cancer ◽

Androgen Receptor ◽

Epithelial Ovarian Cancer ◽

Aryl Hydrocarbon Receptor ◽

Proximal Promoter ◽

Luciferase Reporter ◽

Aryl Hydrocarbon ◽

Paclitaxel Treatment

Background: Epithelial ovarian cancer (EOC) is one of the most lethal gynecological malignancies and presents chemoresistance after chemotherapy treatment. Androgen receptor (AR) has been known to participate in proliferation. Yet the mechanisms of the resistance of this drug and its linkage to the AR remains unclear. Methods: To elucidate AR-related paclitaxel sensitivity, co-IP, luciferase reporter assay and ChIP assay were performed to identify that AR direct-regulated ABCG2 expression under paclitaxel treatment. IHC staining by AR antibody presented higher AR expression in serous-type patients than other types. AR degradation enhancer (ASC-J9) was used to examine paclitaxel-associated and paclitaxel-resistant cytotoxicity in vitro and in vivo. Results: We found AR/aryl hydrocarbon receptor (AhR)-mediates ABCG2 expression and leads to a change in paclitaxel cytotoxicity/sensitivity in EOC serous subtype cell lines. Molecular mechanism study showed that paclitaxel activated AR transactivity and bound to alternative ARE in the ABCG2 proximal promoter region. To identify AR as a potential therapeutic target, the ASC-J9 was used to re-sensitize paclitaxel-resistant EOC tumors upon paclitaxel treatment in vitro and in vivo. Conclusion: The results demonstrated that activation of AR transactivity beyond the androgen-associated biological effect. This novel AR mechanism explains that degradation of AR is the most effective therapeutic strategy for treating AR-positive EOC serous subtype.

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Activation of the aryl hydrocarbon receptor in vivo primes human T cells for interleukin 22 production and inhibits Th17 cells

Annals of the Rheumatic Diseases ◽

10.1136/ard.2010.129668y ◽

2010 ◽

Vol 69 (Suppl 2) ◽

pp. A74-A74

Author(s):

J-M Ramirez ◽

N C Brembilla ◽

O Sorg ◽

R Chicheportiche ◽

T Matthes ◽

...

Keyword(s):

T Cells ◽

Aryl Hydrocarbon Receptor ◽

Th17 Cells ◽

Interleukin 22 ◽

Aryl Hydrocarbon ◽

Human T Cells

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Increased gene copy number of DEFA1/DEFA3 worsens sepsis by inducing endothelial pyroptosis

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1812947116 ◽

2019 ◽

Vol 116 (8) ◽

pp. 3161-3170 ◽

Cited By ~ 10

Author(s):

QiXing Chen ◽

Yang Yang ◽

JinChao Hou ◽

Qiang Shu ◽

YiXuan Yin ◽

...

Keyword(s):

Endothelial Cell ◽

Copy Number ◽

Treatment Options ◽

Gene Copy Number ◽

High Copy Number ◽

Gene Copy ◽

Dependent Manner ◽

Barrier Dysfunction ◽

Specific Expression

Sepsis claims an estimated 30 million episodes and 6 million deaths per year, and treatment options are rather limited. Human neutrophil peptides 1–3 (HNP1–3) are the most abundant neutrophil granule proteins but their neutrophil content varies because of unusually extensive gene copy number polymorphism. A genetic association study found that increased copy number of the HNP-encoding gene DEFA1/DEFA3 is a risk factor for organ dysfunction during sepsis development. However, direct experimental evidence demonstrating that these risk alleles are pathogenic for sepsis is lacking because the genes are present only in some primates and humans. Here, we generate DEFA1/DEFA3 transgenic mice with neutrophil-specific expression of the peptides. We show that mice with high copy number of DEFA1/DEFA3 genes have more severe sepsis-related vital organ damage and mortality than mice with low copy number of DEFA1/DEFA3 or wild-type mice, resulting from more severe endothelial barrier dysfunction and endothelial cell pyroptosis after sepsis challenge. Mechanistically, HNP-1 induces endothelial cell pyroptosis via P2X7 receptor-mediating canonical caspase-1 activation in a NLRP3 inflammasome-dependent manner. Based on these findings, we engineered a monoclonal antibody against HNP-1 to block the interaction with P2X7 and found that the blocking antibody protected mice carrying high copy number of DEFA1/DEFA3 from lethal sepsis. We thus demonstrate that DEFA1/DEFA3 copy number variation strongly modulates sepsis development in vivo and explore a paradigm for the precision treatment of sepsis tailored by individual genetic information.

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