Biased activation of β2-AR/Gi/GRK2 signal pathway attenuated β1-AR sustained activation induced by β1-adrenergic receptor autoantibody

AbstractHeart failure is the terminal stage of many cardiac diseases, in which β1-adrenoceptor (β1-AR) autoantibody (β1-AA) has a causative role. By continuously activating β1-AR, β1-AA can induce cytotoxicity, leading to cardiomyocyte apoptosis and heart dysfunction. However, the mechanism underlying the persistent activation of β1-AR by β1-AA is not fully understood. Receptor endocytosis has a critical role in terminating signals over time. β2-adrenoceptor (β2-AR) is involved in the regulation of β1-AR signaling. This research aimed to clarify the mechanism of the β1-AA-induced sustained activation of β1-AR and explore the role of the β2-AR/Gi-signaling pathway in this process. The beating frequency of neonatal rat cardiomyocytes, cyclic adenosine monophosphate content, and intracellular Ca2+ levels were examined to detect the activation of β1-AA. Total internal reflection fluorescence microscopy was used to detect the endocytosis of β1-AR. ICI118551 was used to assess β2-AR/Gi function in β1-AR sustained activation induced by β1-AA in vitro and in vivo. Monoclonal β1-AA derived from a mouse hybridoma could continuously activate β1-AR. β1-AA-restricted β1-AR endocytosis, which was reversed by overexpressing the endocytosis scaffold protein β-arrestin1/2, resulting in the cessation of β1-AR signaling. β2-AR could promote β1-AR endocytosis, as demonstrated by overexpressing/interfering with β2-AR in HL-1 cells, whereas β1-AA inhibited the binding of β2-AR to β1-AR, as determined by surface plasmon resonance. ICI118551 biasedly activated the β2-AR/Gi/G protein-coupled receptor kinase 2 (GRK2) pathway, leading to the arrest of limited endocytosis and continuous activation of β1-AR by β1-AA in vitro. In vivo, ICI118551 treatment attenuated myocardial fiber rupture and left ventricular dysfunction in β1-AA-positive mice. This study showed that β1-AA continuously activated β1-AR by inhibiting receptor endocytosis. Biased activation of the β2-AR/Gi/GRK2 signaling pathway could promote β1-AR endocytosis restricted by β1-AA, terminate signal transduction, and alleviate heart damage.

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Abstract 15925: Newt Exosomes are Bioactive on Mammalian Heart, Enhancing Proliferation of Rat Cardiomyocytes and Improving Recovery After Myocardial Infarction

Circulation ◽

10.1161/circ.132.suppl_3.15925 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Eleni Tseliou ◽

Liu Weixin ◽

Jackelyn Valle ◽

Baiming Sun ◽

Maria Mirotsou ◽

...

Keyword(s):

Myocardial Infarction ◽

Critical Role ◽

Dermal Fibroblasts ◽

Neonatal Rat ◽

Cardiomyocyte Proliferation ◽

Rat Cardiomyocytes ◽

Mesodermal Cell ◽

Wistar Kyoto

Introduction: Adult newts can regenerate amputated cardiac tissue (and whole limbs) without fibrosis, unlike adult mammals which lack such regenerative capacity. Exosomes are nanoparticles which mediate intercellular communication and play a critical role in therapeutic regeneration. Hypothesis: We isolated exosomes from a newt mesodermal cell line, and evaluated their bioactivity in rat models. Methods: A1 cells, derived from the amputated limb buds of Notopthalmus viridescense (Brockes JP, 1988), were expanded in culture. Exosomes were isolated by polyethylene glycol precipitation of A1-conditioned serum-free media (or media conditioned by human dermal fibroblasts [DF] as a control) followed by centrifugation. Bioactivity was tested in vitro on neonatal rat ventricular myocytes (NRVM), and in vivo on acute myocardial infarction in Wistar-Kyoto rats (250μg or 500μg of A1-exosomes or vehicle [placebo] injected intramyocardially). Functional and histological analyses were performed 3 weeks after therapy. Results: A1-conditioned media yielded ~2.8±1Billion particles/ml of 129±1.1 nm diameter. In vitro, A1-exosomes increased the proliferative capacity of NRVM compared to DF-exosomes (4.98±0.89% vs 0.77±0.33%, p=0.035). Priming of DFs with A1-exosomes increased SDF-1 secretion compared to DF-exosomes (755±117pg/ml vs.368±21pg/ml, p=0.03). In vivo, both A1-exosome doses increased cardiac function compared to placebo (EF= 46±1% in 250μg, 49±4% in 500μg vs 36±1% in placebo, p=0.045 by ANOVA). Scar size was markedly decreased (11±1% in 250μg, 9±2% in 500μg vs 18±2% in placebo, p=0.006 by ANOVA), and infarct wall thickness was increased after A1-exosome treatment (1.7±0.11mm in 250μg, 1.85±0.16mm in 500μg vs 1.17±0.11mm in Placebo, p=0.01 by ANOVA). Donor-specific antibodies were present at barely detectable levels in the serum of animals that had been injected with A1-exosomes. Conclusions: Newt exosomes stimulate rat cardiomyocyte proliferation and improve functional and structural outcomes in rats with myocardial infarction. Characterization of the RNA and protein content of newt exosomes, now in progress, may provide clues regarding conserved (or newt-unique) molecular mediators of therapeutic benefit.

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The Trend of β3-Adrenergic Receptor in the Development of Septic Myocardial Depression: A Lipopolysaccharide-Induced Rat Septic Shock Model

Cardiology ◽

10.1159/000487126 ◽

2018 ◽

Vol 139 (4) ◽

pp. 234-244 ◽

Cited By ~ 7

Author(s):

Ni Yang ◽

Xiao-Lu Shi ◽

Bing-Lun Zhang ◽

Jian Rong ◽

Tie-Ning Zhang ◽

...

Keyword(s):

Septic Shock ◽

Left Ventricular ◽

Neonatal Rat ◽

Myocardial Depression ◽

Rat Cardiomyocytes ◽

Neonatal Cardiomyocytes ◽

Nos Inhibitors ◽

Lps Treatment

Septic shock with low cardiac output is very common in children. However, the mechanism underlying myocardial depression is unclear. The role of β3-AR in the development of myocardial depression in sepsis is unknown. In the present study, we generated an adolescent rat model of hypodynamic septic shock induced by lipopolysaccharide (LPS). Neonatal cardiomyocytes were also treated with LPS to mimic myocardial depression in sepsis, which was confirmed via an in vivo left ventricular hemodynamic study, and measurements of contractility and the Ca2+ transient in isolated adolescent and neonatal cardiomyocytes. After 16 h of LPS treatment, cultured neonatal cardiomyocytes showed a diminished Ca2+ transient amplitude associated with an increase in the β3-AR level. With the addition of a β3-AR agonist, the Ca2+ transient in LPS-treated neonatal rat cardiomyocytes gradually decreased over time; such a change was absent in cells treated with nitric oxide synthase (NOS) inhibitors prior to treatment with a β3-AR agonist. In adolescent rats with septic myocardial depression, cardiac function declined as indicated by decreased MAP, dP/dtmax, and dP/dtmix for 6 h after LPS injection; however, the β3-AR level first increased 2 h after LPS treatment and then decreased 6 h after LPS treatment in the absence of exogenous catecholamines. The results indicate that, in vitro, at the cellular level β3-AR may be involved in the development of myocardial depression (Ca2+ transient depression) in sepsis through NOS signaling pathways; however, in vivo, a complicated mechanism for modulating β3-AR may exist.

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Abstract 107: MicroRNA-31: A Novel Therapeutic Target for Ischemic Heart Disease

Circulation Research ◽

10.1161/res.115.suppl_1.107 ◽

2014 ◽

Vol 115 (suppl_1) ◽

Author(s):

Eliana C Martinez ◽

Shera Lilyanna ◽

Leah A Vardy ◽

Arunmozhiarasi Armugam ◽

Kandiah Jeyaseelan ◽

...

Keyword(s):

Cardiac Function ◽

Target Genes ◽

Subcutaneous Administration ◽

Left Ventricular ◽

Ischemic Heart ◽

Neonatal Rat ◽

Rat Cardiomyocytes ◽

Repressive Effect

MicroRNAs (miRNA), small sequences of non-coding RNA which interact with complementary sequences on the 3’untranslated region of target messenger RNAs to modulate translation, have a pivotal role in the development of the heart and its response to injury. Myocardial infarction (MI) triggers a dynamic miRNA response with the potential of yielding therapeutic targets. Following miRNA array profiling in rat hearts 2, 7 and 14 days after MI induced by coronary ligation, we identified a progressive time-dependent up-regulation of miR-31 compared to sham rats. Increase of miR-31 in heart tissue in the acute and subacute phases after MI (up to 90-fold) was also detected by Real-Time PCR (P=0.02 at day 2; P<0.0001 at days 7 and 14, vs. sham). We found that miR-31 has a repressive effect on tissue mRNA expression of cardiac troponin-T (TNNT2), E2F transcription factor 6 (E2F6) and mineralocorticoid receptor (NR3C2). Reporter gene assays showed that miR-31 targets the 3′UTR of these genes, with a marked repressive effect on TNNT2. In vitro, exposure to hypoxia significantly induced the expression of miR-31 in neonatal rat cardiomyocytes (nRCM), rat cardiac fibroblasts (nRCF) and cardiomyoblasts (H9C2) and suppressed the expression of TNNT2, E2F6 and NR3C2 in nRCM and H9C2 cells, and of E2F6 and NR3C2 in nRCF. LNA-based oligonucleotide inhibition of miR-31(miR-31i) in vitro reversed its repressive effect on translation from target genes. Therapeutic modulation of miR-31 expression in vivo after MI via subcutaneous administration of miR-31i (25mg/Kg/q2w) in rats, led to cardiac repression of miR-31 and subsequent enhanced expression of target genes. Also, miR-31i led to preservation of cardiac function and structure by day 14 after treatment. An absolute 10% improvement in left ventricular (LV) ejection fraction (EF) was observed in miR-31i-treated rats from day 2 to 16 after MI, while control rats that received scrambled LNA inhibitor or placebo displayed 23% deterioration in EF (n=6-8/group, P<0.0001). We conclude that miR-31 induction after MI is deleterious to cardiac function and plays an important role in adverse remodeling, while its therapeutic inhibition in vivo ameliorates cardiac dysfunction and prevents the development of post-ischemic heart failure.

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Abstract 285: Cardiac Inflammation and Fibrosis Induced by Heart Failure Are Reversed by Short-Duration Estrogen Therapy

Circulation Research ◽

10.1161/res.111.suppl_1.a285 ◽

2012 ◽

Vol 111 (suppl_1) ◽

Author(s):

Andrea Iorga ◽

Rangarajan Nadadur ◽

Salil Sharma ◽

Jingyuan Li ◽

Mansoureh Eghbali

Keyword(s):

Heart Failure ◽

Estrogen Therapy ◽

Pressure Overload ◽

Decompensated Heart Failure ◽

Left Ventricular ◽

Neonatal Rat ◽

In Vivo Model ◽

Anti Inflammatory

Heart failure is generally characterized by increased fibrosis and inflammation, which leads to functional and contractile defects. We have previously shown that short-term estrogen (E2) treatment can rescue pressure overload-induced decompensated heart failure (HF) in mice. Here, we investigate the anti-inflammatory and anti-fibrotic effects of E2 on reversing the adverse remodeling of the left ventricle which occurs during the progression to heart failure. Trans-aortic constriction procedure was used to induce HF. Once the ejection fraction reached ∼30%, one group of mice was sacrificed and the other group was treated with E2 (30 αg/kg/day) for 10 days. In vitro, co-cultured neonatal rat ventricular myocytes and fibroblasts were treated with Angiotensin II (AngII) to simulate cardiac stress, both in the presence or absence of E2. In vivo RT-PCR showed that the transcript levels of the pro-fibrotic markers Collagen I, TGFβ, Fibrosin 1 (FBRS) and Lysil Oxidase (LOX) were significantly upregulated in HF (from 1.00±0.16 to 1.83±0.11 for Collagen 1, 1±0.86 to 4.33±0.59 for TGFβ, 1±0.52 to 3.61±0.22 for FBRS and 1.00±0.33 to 2.88±0.32 for LOX) and were reduced with E2 treatment to levels similar to CTRL. E2 also restored in vitro AngII-induced upregulation of LOX, TGFβ and Collagen 1 (LOX:1±0.23 in CTRL, 6.87±0.26 in AngII and 2.80±1.5 in AngII+E2; TGFβ: 1±0.08 in CTRL, 3.30±0.25 in AngII and 1.59±0.21 in AngII+E2; Collagen 1: 1±0.05 in CTRL.2±0.01 in AngII and 0.65±0.02 (p<0.05, values normalized to CTRL)). Furthermore, the pro-inflammatory interleukins IL-1β and IL-6 were upregulated from 1±0.19 to 1.90±0.09 and 1±0.30 to 5.29±0.77 in the in vivo model of HF, respectively, and reversed to CTRL levels with E2 therapy. In vitro, IL-1β was also significantly increased ∼ 4 fold from 1±0.63 in CTRL to 3.86±0.14 with AngII treatment and restored to 1.29±0.77 with Ang+E2 treatment. Lastly, the anti-inflammatory interleukin IL-10 was downregulated from 1.00±0.17 to 0.49±0.03 in HF and reversed to 0.67±0.09 in vivo with E2 therapy (all values normalized to CTRL). This data strongly suggests that one of the mechanisms for the beneficial action of estrogen on left ventricular heart failure is through reversal of inflammation and fibrosis.

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Bakuchiol protects against pathological cardiac hypertrophy by blocking NF-κB signaling pathway

Bioscience Reports ◽

10.1042/bsr20181043 ◽

2018 ◽

Vol 38 (5) ◽

Cited By ~ 2

Author(s):

Zheng Wang ◽

Lu Gao ◽

Lili Xiao ◽

Lingyao Kong ◽

Huiting Shi ◽

...

Keyword(s):

Cardiac Hypertrophy ◽

Signaling Pathway ◽

Pressure Overload ◽

Neonatal Rat ◽

Oral Gavage ◽

Aortic Banding ◽

Rat Cardiomyocytes ◽

Pathological Cardiac Hypertrophy ◽

First Time

Bakuchiol (Bak), a monoterpene phenol isolated from the seeds of Psoralea corylifolia, has been widely used to treat a large variety of diseases in both Indian and Chinese folkloric medicine. However, the effects of Bak on cardiac hypertrophy remain unclear. Therefore, the present study was designed to determine whether Bak could alleviate cardiac hypertrophy. Mice were subjected to aortic banding (AB) to induce cardiac hypertrophy model. Bak of 1 ml/100 g body weight was given by oral gavage once a day from 1 to 8 weeks after surgery. Our data demonstrated for the first time that Bak could attenuate pressure overload-induced cardiac hypertrophy and could attenuate fibrosis and the inflammatory response induced by AB. The results further revealed that the effect of Bak on cardiac hypertrophy was mediated by blocking the activation of the NF-κB signaling pathway. In vitro studies performed in neonatal rat cardiomyocytes further proved that the protective effect of Bak on cardiac hypertrophy is largely dependent on the NF-κB pathway. Based on our results, Bak shows profound potential for its application in the treatment of pathological cardiac hypertrophy, and we believe that Bak may be a promising therapeutic candidate to treat cardiac hypertrophy and heart failure.

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Abstract 631 ADAM12 Is An Important Regulator Of Myocyte Apoptosis Induced By β-adrenergic Receptor Stimulation

Circulation ◽

10.1161/circ.116.suppl_16.ii_115-c ◽

2007 ◽

Vol 116 (suppl_16) ◽

Author(s):

Hang Xi ◽

Khadija Rafiq ◽

Marie Hanscom ◽

Rachid Seqqat ◽

Nikolay L Malinin ◽

...

Keyword(s):

Ventricular Myocytes ◽

Left Ventricular ◽

Surface Proteins ◽

Neonatal Rat ◽

Human Heart Failure ◽

Activation Mechanisms ◽

Myocyte Apoptosis ◽

Protease Deficient

ADAM (A Disintegrin And Metalloprotease)12 is a member of a family of cell surface proteins with protease and cell-binding activities. Recent work showed ADAM12 up-regulation in human heart failure. However, the activation mechanisms of ADAM12 in the heart are obscure. We hypothesized that β-adrenergic receptors (AR) stimulation regulates ADAM12 activation in neonatal rat ventricular myocytes (NRVMs) in-vitro and after injection of isoproterenol (ISO) in-vivo. Wistar rats received a single injection of ISO (5 mg/kg) and were sacrificed 6, 24 and 72 hrs later. In comparison with controls, left ventricular function was impaired in rats 24 hrs after ISO injection and started to improve at 72 hrs. The fraction of myocytes undergoing apoptosis peaked 24 hrs after ISO injection and declined thereafter. ADAM12 protein was reduced in hearts from ISO treated animals at 6 hrs, pointing to a possible increase in ADAM12 proteolytic activity. However, both ADAM12 expression and activation were significantly up-regulated at 24 and 72 hrs after ISO injection. We therefore assessed whether ADAM12 activation was involved in myocyte apoptosis secondary to excess exposure of catecholamine. Acute stimulation with ISO (10 μM, 30 min to 3 hrs) induced accumulation of ADAM12 N-terminal cleavage product in conditioned medium, demonstrating activation of the ADAM metalloprotease activity. However, chronic stimulation with ISO for 24 hrs and 48 hrs significantly increased both ADAM12 expression and secretion. This ISO-induced ADAM12 expression/activation was mediated through β 1 -AR stimulation and was dependent on intracellular calcium elevation and protein kinase C activation. Adenoviral expression of an ADAM12 protease-deficient mutant (ADAM12DeltaMP) blocks β-AR-induced myocyte apoptosis, while transduction of NRVMs with adenovirus harboring ADAM12 significantly increased myocyte apoptosis. These data suggest that ADAM12 is a regulator of myocyte apoptosis induced by β-AR in NRVMs and may play an important autocrine role in mediating the effects of β-AR on myocardial remodeling.

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Abstract 165: The 18 kDa FGF-2 Prevents the Doxorubicin-induced Cardiac Damage and Amp-activated Kinase Activation, in vitro and in vivo

Circulation Research ◽

10.1161/res.117.suppl_1.165 ◽

2015 ◽

Vol 117 (suppl_1) ◽

Author(s):

Navid Koleini ◽

Jon Jon Santiago ◽

Barbara E Nickel ◽

Robert Fandrich ◽

Davinder S Jassal ◽

...

Keyword(s):

Molecular Weight ◽

Cell Death ◽

Left Ventricular ◽

Left Ventricular Ejection ◽

Wild Type ◽

Rat Cardiomyocytes ◽

Ventricular Ejection Fraction ◽

Compound C

Introduction: Protection of the heart from chemotherapeutic (Doxorubicin, DOX) drug-induced toxicity is a desirable goal, to limit side effects of cancer treatments. DOX toxicity has been linked to the activation (phosphorylation) of the AMP-activated kinase, AMPK. The 18 kDa low molecular weight isoform of fibroblast growth factor 2 (Lo-FGF-2) is a known cardioprotective and cytoprotective agent. In this study we have tested the ability of Lo-FGF-2 to protect from DOX-induced damage in rat cardiomyocytes in vitro, and in transgenic mouse models in vivo, in relation to AMPK activation. Methods: Rat neonatal cardiomyocytes in culture were exposed to DOX (0.5 μM) in the presence or absence of pre-treatment Lo-FGF-2 (10 ng/ml). Compound C was used to block phosphorylation (activity) of AMPK. Levels of cell viability/death (using Calcein-AM/Propidium iodide assay), phospho -and total AMPK, and apoptotic markers such as active caspase 3 were analyzed. In addition, transgenic mice expressing only Lo-FGF2, and wild type mice, expressing both high molecular weight (Hi-FGF2) as well as Lo-FGF2 were subjected to DOX injection (20 mg/kg, intraperitoneal); echocardiography was used to examine cardiac function at baseline and at 10 days post-DOX. Results: DOX-induced cell death of cardiomyocytes in culture was maximal at 24 hours post-DOX coinciding with significantly increased in activated (phosphorylated) AMPK. Compound C attenuated DOX-induced cardiomyocyte loss. Pre-incubation with Lo-FGF-2 decreased DOX induced cell death, and also attenuated the phosphorylation of AMPK post-DOX. Relative levels of phospho-AMPK were lower in the hearts of Lo-FGF2-expressing male mice compared to wild type. DOX-induced loss of contractile function (left ventricular ejection fraction and endocardial velocity) was negligible in Lo-FGF2-expressing mice but significant in wild type mice. Conclusion: Lo-FGF-2 protects the heart from DOX-induced damage in vitro and in vivo, by a mechanism likely involving an attenuation of AMPK activity.

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Overexpression of TIMP3 Protects Against Cardiac Ischemia/Reperfusion Injury by Inhibiting Myocardial Apoptosis Through ROS/Mapks Pathway

Cellular Physiology and Biochemistry ◽

10.1159/000485401 ◽

2017 ◽

Vol 44 (3) ◽

pp. 1011-1023 ◽

Cited By ~ 16

Author(s):

Hui Liu ◽

Xibo Jing ◽

Aiqiao Dong ◽

Baobao Bai ◽

Haiyan Wang

Keyword(s):

Myocardial Infarct ◽

Ischemia Reperfusion ◽

Neonatal Rat ◽

Tunel Staining ◽

Ros Production ◽

Rat Cardiomyocytes ◽

Doxorubicin Treatment ◽

Myocardial Apoptosis

Background/Aims: Myocardial ischemia/reperfusion (I/R) injury remains a great challenge in clinical therapy. Tissue inhibitor of metalloproteinases 3 (TIMP3) plays a crucial role in heart physiological and pathophysiological processes. However, the effects of TIMP3 on I/R injury remain unknown. Methods: C57BL/6 mice were infected with TIMP3 adenovirus by local delivery in myocardium followed by I/R operation or doxorubicin treatment. Neonatal rat cardiomyocytes were pretreated with TIMP3 adenovirus prior to anoxia/reoxygenation (A/R) treatment in vitro. Histology, echocardiography, in vivo phenotypical analysis, flow cytometry and western blotting were used to investigate the altered cardiac function and underlying mechanisms. Results: The results showed that upregulation of TIMP3 in myocardium markedly inhibited myocardial infarct areas and the cardiac dysfunction induced by I/R or by doxorubicin treatment. TUNEL staining revealed that TIMP3 overexpression attenuated I/R-induced myocardial apoptosis, accompanied by decreased Bax/Bcl-2 ratio, Cleaved Caspase-3 and Cleaved Caspase-9 expression. In vitro, A/R-induced cardiomyocyte apoptosis was abrogated by pharmacological inhibition of reactive oxygen species (ROS) production or MAPKs signaling. Attenuation of ROS production reversed A/R-induced MAPKs activation, whereas MAPKs inhibitors showed on effect on ROS production. Furthermore, in vivo or in vitro overexpression of TIMP3 significantly inhibited I/R- or A/R-induced ROS production and MAPKs activation. Conclusion: Our findings demonstrate that TIMP3 upregulation protects against cardiac I/R injury through inhibiting myocardial apoptosis. The mechanism may be related to inhibition of ROS-initiated MAPKs pathway. This study suggests that TIMP3 may be a potential therapeutic target for the treatment of I/R injury.

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Mechanical stimulation of organogenic cardiomyocyte growth in vitro

AJP Cell Physiology ◽

10.1152/ajpcell.1996.270.5.c1284 ◽

1996 ◽

Vol 270 (5) ◽

pp. C1284-C1292 ◽

Cited By ~ 38

Author(s):

H. H. Vandenburgh ◽

R. Solerssi ◽

J. Shansky ◽

J. W. Adams ◽

S. A. Henderson

Keyword(s):

Mechanical Load ◽

Mechanical Stretch ◽

Neonatal Rat ◽

Cardiomyocyte Hypertrophy ◽

Heart Cells ◽

Mechanical Stimuli ◽

Rat Cardiomyocytes ◽

Morphological Alterations

Adherent cultures of neonatal rat cardiomyocytes were subjected to progressive, unidirectional lengthening for 2-4 days in serum-containing medium. This mechanical stretch (25% increase in initial length each day) simulates the eccentric mechanical load placed on in vivo heart cells by increases in postnatal blood pressure and volume. The in vitro mechanical stimuli initiated a number of morphological alterations in the confluent cardiomyocyte population which were similar to those occurring during in vivo heart growth. These include cardiomyocyte organization into parallel arrays of rod-shaped cells, increased cardiomyocyte binucleation, and cardiomyocyte hypertrophy by longitudinal cell growth. Stretch stimulated DNA synthesis in the noncardiomyocyte population but not in the cardiomyocytes. Myosin heavy chain (MHC) content increased 62% over 4 days of stretch and included increased accumulation of both fetal beta-MHC and adult alpha-MHC isoforms. This new model of stretch-induced cardiomyocyte hypertrophy may assist in examining some of the complex mechanogenic growth processes that occur in the rapidly enlarging neonatal heart.

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JARID1B promotes colorectal cancer proliferation and Wnt/β-catenin signaling via decreasing CDX2 level

10.21203/rs.3.rs-17618/v1 ◽

2020 ◽

Author(s):

Da Huang ◽

Fan Xiao ◽

Fuzhou Hua ◽

Zhenzhong Luo ◽

Zhaoxia Huang ◽

...

Keyword(s):

Colorectal Cancer ◽

Signaling Pathway ◽

Critical Role ◽

Predictive Marker ◽

Cancer Proliferation ◽

Poor Overall Survival ◽

Downstream Target ◽

Cellular Analysis

Abstract Background: Jumonji AT-rich interactive domain 1B(JARID1B) has been shown to be upregulated in many human cancers and plays a critical role in the development of cancers cells. Nevertheless, its functional role in colorectal cancer (CRC) progression is not fully understood. Methods: Herein, JARID1B expression levels were detected in clinical CRC samples by western blotting and qRT-PCR. DLD-1 cells with JARID1B knockdown or overexpression by stably transfected plasmids were used in vitro and in vivo study. Colony formation, 5-ethynyl-20-deoxyuridine (EdU) and Real Time Cellular Analysis(RTCA) assays were used to detect cell proliferation and growth. Transcriptome and CHIP assays were used to examine the molecular biology changes and molecular interaction in these cells. Nude mice was utilized to study the correlation of JARID1B and tumor growth in vivo. Results: Here, we first observed that JARID1B was significantly upregulated in CRC tissue compared to adjacent normal tissues. In CRC patients, JARID1B high expression was positively relation with poor overall survival. Multivariate analyses revealed that high JARID1B expression was an independent predictive marker for the poor prognosis of CRC. In addition, we found that JARID1B promoted CRC cells proliferation by Wnt/β-catenin signaling pathway. Further studies demonstrated CDX2 as a downstream target of JARID1B, and our data demonstrated that CDX2 is crucial for JARID1B -mediated Wnt/β-catenin signaling pathway. Mechanistically, we demonstrated that JARID1B regulated CDX2 expression through demethylation of H3K4me3. Conclusions: CDX2 inhibited by JARID1B-derived H3K4me3 methylation promoted cells proliferation of CRC via Wnt/β-catenin signaling pathway. Therefore, our studies provided a novel insight into the role of JARID1B in CRC cells proliferation and potential new molecular target for treating CRC.

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