Inhibition of β-adrenergic receptor trafficking in adult cardiocytes by MAP4 decoration of microtubules

Decreased β-adrenergic receptor (β-AR) number occurs both in animal models of cardiac hypertrophy and failure and in patients. β-AR recycling is an important mechanism for the β-AR resensitization that maintains a normal complement of cell surface β-ARs. We have shown that 1) in severe pressure overload cardiac hypertrophy, there is extensive microtubule-associated protein 4 (MAP4) decoration of a dense microtubule network; and 2) MAP4 microtubule decoration inhibits muscarinic acetylcholine receptor recycling in neuroblastoma cells. We asked here whether MAP4 microtubule decoration inhibits β-AR recycling in adult cardiocytes. [3H]CGP-12177 was used as a β-AR ligand, and feline cardiocytes were isolated and infected with adenovirus containing MAP4 (AdMAP4) or β-galactosidase (Adβ-gal) cDNA. MAP4 decorated the microtubules extensively only in AdMAP4 cardiocytes. β-AR agonist exposure reduced cell surface β-AR number comparably in AdMAP4 and Adβ-gal cardiocytes; however, after agonist withdrawal, the cell surface β-AR number recovered to 78.4 ± 2.9% of the pretreatment value in Adβ-gal cardiocytes but only to 56.8 ± 1.4% in AdMAP4 cardiocytes ( P < 0.01). This result was confirmed in cardiocytes isolated from transgenic mice having cardiac-restricted MAP4 overexpression. In functional terms of cAMP generation, β-AR agonist responsiveness of AdMAP4 cells was 47% less than that of Adβ-gal cells. We conclude that MAP4 microtubule decoration interferes with β-AR recycling and that this may be one mechanism for β-AR downregulation in heart failure.

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Abstract 837: Beta1 And Beta2 Adrenergic Receptor Transgenic Mice Display Distinct MicroRNA Expression Patterns That Converge On The Hypertrophic Signature

Circulation ◽

10.1161/circ.116.suppl_16.ii_162-d ◽

2007 ◽

Vol 116 (suppl_16) ◽

Author(s):

Danish Sayed ◽

Shweta Rane ◽

Leng-Yi Chen ◽

Minzhen He ◽

Jacqueline Lypowy ◽

...

Keyword(s):

Cardiac Hypertrophy ◽

Adrenergic Receptor ◽

Mapk Pathway ◽

Expression Patterns ◽

Pressure Overload ◽

Mapk Signaling ◽

Compensatory Hypertrophy ◽

Over Expression ◽

Mrna Targets ◽

Dose Dependent

MicroRNA (miRNA) are ~22 ribonucleotides-long, with a potential to recognize multiple mRNA targets guided by sequence complimentarity. This class of molecules is functionally versatile, with the capacity to specifically inhibit translation, as well as, induce mRNA degradation, through targeting the 3′-untranslated regions. The levels of individual miRNA vary under different developmental, biological, or pathological conditions, thus, implicating them in normal and pathological cellular attributes. We have previously reported a miRNA signature that distinguishes pressure-overload compensatory hypertrophy by recapitulating the neonatal pattern. We hypothesized that this ’signature’ might aid in discriminating the underlying molecular differences in genetic models of cardiac hypertrophy, as seen in the beta1 and 2 adrenergic receptor (B1AR and B2AR) transgenic (Tg) mice. To address this, we used microarray analysis of RNA isolated from the hearts of 3 months old B1AR and B2AR mice. In general, while both mice exhibited an overlap with the hypertrophy signature including, upregulation of miR-21 and downregulation of miR-133a, miR-133b, and miR-185, the B2-AR Tg exhibited a more extensive overlap with the hypertrophy pattern, which further included upregulation of miR-199a*, miR-214, and miR-15b. To understand the functional significance of these miRNA in myocyte hypertrophy, we cloned them and their anti-sense sequences into adenoviral vectors. Significantly, over-expression miR-21 resulted in a, dose-dependent, branching (sprouting) of the cells. Computational predictions by ’TargetScanS’ identified sprouty as potential target. Subsequently, we confirmed down-regulation of sprouty by over-expression of miR-21 and vice versa. Sprouty is a known inhibitor of the Ras-MAPK signaling pathway and is, concordantly, downregulated in many forms of cancer. In the heart, sprouty has been suggested to control myocyte size and vascularization during cardiac hypertrophy. Thus, we propose that B1AR and B2AR Tg models exhibit distinct miRNA profiles that converge on that of pressure-overload cardiac hypertrophy. Moreover, the commonly over-expressed miR-21 plays a role in downregulating sprouty, an antagonist of the Ras-MAPK pathway.

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Inhibition of G protein-coupled receptor trafficking in neuroblastoma cells by MAP 4 decoration of microtubules

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00410.2002 ◽

2002 ◽

Vol 283 (6) ◽

pp. H2379-H2388 ◽

Cited By ~ 9

Author(s):

Guangmao Cheng ◽

Yoshihiro Iijima ◽

Yuji Ishibashi ◽

Dhandapani Kuppuswamy ◽

George Cooper

Keyword(s):

G Protein ◽

Muscarinic Receptor ◽

Receptor Binding ◽

Neuroblastoma Cells ◽

Pressure Overload ◽

G Protein Coupled Receptors ◽

Structural Protein ◽

Microtubule Network ◽

Intact Cells ◽

G Protein Coupled

One mechanism for the reappearance of G protein-coupled receptors after agonist activation is microtubule-based transport. In pressure-overload cardiac hypertrophy, there is downregulation of G protein-coupled receptors and the appearance of a densified microtubule network extensively decorated by a microtubule-associated protein, MAP 4. Our hypothesis is that overdecoration of a dense microtubule network with this structural protein, as in hypertrophied myocardium, would impede receptor recovery. We tested this hypothesis by studying muscarinic acetylcholine receptor (mAChR) internalization and recovery after agonist stimulation in neuroblastoma cells. Exposure of cells to carbachol, a muscarinic receptor agonist, decreased membrane receptor binding activity. After carbachol withdrawal, receptor binding recovered toward the initial value. When microtubules were depolymerized before carbachol withdrawal, mAChR recovery was only 44% of that in intact cells. Cells were then infected with an adenovirus containing MAP 4 cDNA. MAP 4 protein decorated the microtubules extensively, and receptor recovery upon carbachol withdrawal was reduced to 54% of control. Thus muscarinic receptor recovery after agonist exposure is microtubule dependent, and MAP 4 decoration of microtubules inhibits receptor recovery.

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Plasma membrane-specific deficiency in cardiac beta-adrenergic receptor in streptozocin-diabetic rats

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1989.257.2.e127 ◽

1989 ◽

Vol 257 (2) ◽

pp. E127-E132 ◽

Cited By ~ 3

Author(s):

A. Kashiwagi ◽

Y. Nishio ◽

Y. Saeki ◽

Y. Kida ◽

M. Kodama ◽

...

Keyword(s):

Cell Surface ◽

Adrenergic Receptor ◽

Insulin Treatment ◽

Diabetic Rats ◽

Cell Surface Receptor ◽

Beta Adrenergic Receptor ◽

Beta Adrenergic ◽

Receptor Concentration ◽

Cgp 12177

Cell surface [3H]CGP 12177 binding sites in 10-wk streptozocin-diabetic rats decreased by 41% (P less than 0.01) compared with that in the control rats. In contrast, there was no difference in the total cell receptor concentration between the control and the diabetic rats, which was measured by hydrophobic antagonist [125I]-iodocyanopindolol binding. Forty-eight-hour in vivo insulin treatment significantly (P less than 0.05) increased cell surface beta-adrenergic receptor concentration by 37% above that in diabetic rats without any change in total receptor concentration in the cells. However in vitro treatment of 8 nM insulin, 33 mM glucose, or 10 mM 3-hydroxybutyrate for 2 h showed no effect on [3H]CGP 12177 binding. In contrast, 10 microM isoproterenol-dependent decrease and the recovery of cell surface receptors after the removal of the agonist were significantly (P less than 0.01) impaired in diabetic rats compared with those of control rats. These results indicate that only cell surface beta-adrenergic receptors decrease in diabetic rats, which may be associated with abnormalities in the receptor distribution. The decrease in cell surface receptor number closely associates with the diabetic state and is reversed by the short-term insulin treatment.

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Physiological Induction of a β-Adrenergic Receptor Kinase Inhibitor Transgene Preserves β-Adrenergic Responsiveness in Pressure-Overload Cardiac Hypertrophy

Circulation ◽

10.1161/01.cir.102.22.2751 ◽

2000 ◽

Vol 102 (22) ◽

pp. 2751-2757 ◽

Cited By ~ 22

Author(s):

Brian S. Manning ◽

Kyle Shotwell ◽

Lan Mao ◽

Howard A. Rockman ◽

Walter J. Koch

Keyword(s):

Cardiac Hypertrophy ◽

Adrenergic Receptor ◽

Kinase Inhibitor ◽

Pressure Overload ◽

Receptor Kinase

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Basis for MAP4 Dephosphorylation-related Microtubule Network Densification in Pressure Overload Cardiac Hypertrophy

Journal of Biological Chemistry ◽

10.1074/jbc.m110.148650 ◽

2010 ◽

Vol 285 (49) ◽

pp. 38125-38140 ◽

Cited By ~ 18

Author(s):

Guangmao Cheng ◽

Masaru Takahashi ◽

Anandakumar Shunmugavel ◽

J. Grace Wallenborn ◽

Anna A. DePaoli-Roach ◽

...

Keyword(s):

Cardiac Hypertrophy ◽

Pressure Overload ◽

Microtubule Network

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Pressure overload causes cardiac hypertrophy in β1-adrenergic and β2-adrenergic receptor double knockout mice

Journal of Hypertension ◽

10.1097/01.hjh.0000203843.41937.2a ◽

2006 ◽

Vol 24 (3) ◽

pp. 563-571 ◽

Cited By ~ 14

Author(s):

Sergio Palazzesi ◽

Marco Musumeci ◽

Liviana Catalano ◽

Mario Patrizio ◽

Tonino Stati ◽

...

Keyword(s):

Cardiac Hypertrophy ◽

Knockout Mice ◽

Adrenergic Receptor ◽

Pressure Overload ◽

Double Knockout ◽

Β2 Adrenergic Receptor

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Abstract 59: Role of Follistatin 315 in Regulating Cardiac Hypertrophy in Physiology and Pathophysiology

Circulation Research ◽

10.1161/res.117.suppl_1.59 ◽

2015 ◽

Vol 117 (suppl_1) ◽

Author(s):

Zhaobin Xu ◽

Alisa D Blazek ◽

Eric Beck ◽

Jenna Alloush ◽

Jackie Li ◽

...

Keyword(s):

Heart Failure ◽

Cell Surface ◽

Cardiac Hypertrophy ◽

Genetically Modified ◽

Pressure Overload ◽

Wild Type ◽

Surface Binding ◽

Post Surgery ◽

Genetically Modified Mice

Heart failure is characterized by initial compensatory changes, including the myocyte hypertrophy, chamber dilation, and matrix remodeling, that proceed until progressive dysfunction produces end stage heart failure and mortality. Recently, the roles of secreted factors in the heart that could regulate pathological hypertrophy, including follistatin (FST) and related molecules, have been examined by various investigators. FST is a molecule that blocks secretion of follicle-stimulating hormone from the pituitary and regulates members of the transforming growth factor beta (TGF-β) family including myostatin. Here we tested the effects of a particular FST isoform, FST288, on heart function in mice. The gene encoding FST produces three isoforms that differ in biological activities and cell surface binding capabilities. The FST315 isoform contains all six exons, and proteolytic cleavage of the FST315 C-terminal tail results in production of FST303. The lack of exon 6, which codes for the acidic C-terminal tail of the putative full-length protein, results in FST288. The missing acidic C-terminal tail region found in soluble FST315 allows FST288 to bind cell surface heparin-sulfated proteoglycans, accounting for the differential actions of these FST isoforms. Since mice that are null for the FST gene die embryonically, we used genetically modified mice that express only the FST288 isoform to test the role of FST315 in adult heart. Examination of these animals suggests that the loss of FST315 expression has limited effects on the heart at the resting state. When these mice are subjected to pressure overload through transverse aortic constriction (TAC) surgery they appear to be resistant to the compensatory cardiac hypertrophy present in wild type mice by 4 weeks post surgery. Both cardiac structure (examined by histology) and function (as measured by echocardiography and pressure/volume loops) following TAC are improved in the genetically modified mice when compared to wild type mice. This response is likely due to modification of the myostatin signaling pathway, one of the major targets of FST315. Overall, our data illustrates that FST315 is an important contributor to the progression of pressure overload induced cardiac hypertrophy.

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