scholarly journals Ablation of 3-Phosphoinositide-Dependent Protein Kinase 1 (PDK1) in Vascular Endothelial Cells Enhances Insulin Sensitivity by Reducing Visceral Fat and Suppressing Angiogenesis

2012 ◽  
Vol 26 (1) ◽  
pp. 95-109 ◽  
Author(s):  
Kazuhito Tawaramoto ◽  
Ko Kotani ◽  
Mitsuru Hashiramoto ◽  
Yukiko Kanda ◽  
Tomoki Nagare ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Insulin Sensitivity ◽  
Protein Kinase ◽  
Vascular Endothelial Cells ◽  
Whole Body ◽  
Vascular Endothelial ◽  
Dependent Protein Kinase ◽  
Dependent Protein

Abstract The phosphatidylinositol 3-kinase signaling pathway in vascular endothelial cells is important for systemic angiogenesis and glucose metabolism. In this study, we addressed the precise role of the 3-phosphoinositide-dependent protein kinase 1 (PDK1)-regulated signaling network in endothelial cells in vivo, using vascular endothelial PDK1 knockout (VEPDK1KO) mice. Surprisingly, VEPDK1KO mice manifested enhanced glucose tolerance and whole-body insulin sensitivity due to suppression of their hepatic glucose production with no change in either peripheral glucose disposal or even impaired vascular endothelial function at 6 months of age. When mice were fed a standard diet at 6 months of age and a high-fat diet at 3 months of age, hypertrophy of epididymal adipose tissues was inhibited, adiponectin mRNA was significantly increased, and mRNA of MCP1, leptin, and TNFα was decreased in the white adipose tissue of VEPDK1KO mice in comparison with controls. Consequently, both the circulating adiponectin levels and the activity of hepatic AMP-activated protein kinase were significantly increased, subsequently enhancing whole-body insulin sensitivity and energy expenditure with increased hepatic fatty acid oxidation in VEPDK1KO mice. These results provide the first in vivo evidence that lowered angiogenesis through the deletion of PDK1 signaling not only interferes with the growth of adipose tissue but also induces increased energy expenditure due to amelioration of the adipocytokine profile. This demonstrates an unexpected role of PDK1 signaling in endothelial cells on the maintenance of proper glucose homeostasis through the regulation of adipocyte development.

Endothelial cell protein kinase G inhibits release of EDHF through a PKG-sensitive cation channel

2001 ◽  
Vol 280 (3) ◽  
pp. H1272-H1277 ◽  
Author(s):  
K. A. Dora ◽  
C. J. Garland ◽  
H. Y. Kwan ◽  
X. Yao
Keyword(s):  
Endothelial Cells ◽  
Protein Kinase ◽  
Vascular Endothelial Cells ◽  
Cation Channel ◽  
Mesenteric Arteries ◽  
Protein Kinase G ◽  
Cell Protein ◽  
Vascular Endothelial ◽  
Inside Out

The release of dilator agents from vascular endothelial cells is modulated by changes in cytosolic Ca2+ concentration ([Ca2+]i). In this study, we demonstrate the presence of a Ca2+-permeable cation channel in inside-out membrane patches of endothelial cells isolated from small mesenteric arteries. The activity of the channel is increased by KT-5823, a highly selective inhibitor of protein kinase G (PKG), while it is decreased by direct application of active PKG. Application of KT-5823 induces Ca2+ influx in the endothelial cells isolated from small mesenteric arteries, and it also causes endothelium-dependent relaxations in isolated small mesenteric arteries. KT-5823-induced relaxations in small mesenteric arteries are greatly reduced by 35 mM K+ or 50 nM charybdotoxin + 50 nM apamin, suggesting that endothelium-derived hyperpolarizing factor (EDHF) is the participating dilator. The involvement of EDHF is further supported by experiments in which the relaxations of small mesenteric arteries are shown to be accompanied by membrane repolarization. These data strongly argue for a major role of a PKG-sensitive cation channel in modulating the release of EDHF from endothelial cells in rat small mesenteric arteries.

scholarly journals In Vivo Selection of Kinase-responsive RNA Elements Controlling Alternative Splicing

2009 ◽  
Vol 284 (24) ◽  
pp. 16191-16201 ◽  
Author(s):  
Hongzhao Li ◽  
Guodong Liu ◽  
Jiankun Yu ◽  
Wenguang Cao ◽  
Vincent G. Lobo ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Protein Kinase ◽  
Cultured Cells ◽  
Feedback Regulation ◽  
Dependent Protein Kinase ◽  
Dependent Protein ◽  
Rna Elements ◽  
Cell Signals

Alternative pre-mRNA splicing is often controlled by cell signals, for example, those activating the cAMP-dependent protein kinase (PKA) or the Ca2+/calmodulin-dependent protein kinase IV (CaMKIV). We have shown that CaMKIV regulates alternative splicing through short CA repeats and hnRNP L. Here we use a splicing reporter that shows PKA/CaMKIV promotion of exon inclusion to select from exons containing random 13-nt sequences for RNA elements responsive to the kinases in cultured cells. This selection not only identified both PKA- and CaMKIV-responsive elements that are similar to the CaMKIV-responsive RNA element 1 (CaRRE1) or CA repeats, but also A-rich elements not previously known to respond to these kinases. Consistently, hnRNP L is identified as a factor binding the CA-rich elements. Analyses of the motifs in the highly responsive elements indicate that they are indeed critical for the kinase effect and are enriched in alternative exons. Interestingly, a CAAAAAA motif is sufficient for the PKA/CaMKIV-regulated splicing of the exon 16 of the CaMK kinase β1 (CaMKK2) transcripts, implying a role of this motif in signaling cross-talk or feedback regulation between these kinases through alternative splicing. Therefore, these experiments identified a group of RNA elements responsive to PKA and CaMKIV from in vivo selection. This also provides an approach for selecting RNA elements similarly responsive to other cell signals controlling alternative splicing.

scholarly journals Host EPAC1 Modulates Rickettsial Adhesion to Vascular Endothelial Cells via Regulation of ANXA2 Y23 Phosphorylation

Pathogens ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1307
Author(s):  
Zhengchen Su ◽  
Thomas R. Shelite ◽  
Yuan Qiu ◽  
Qing Chang ◽  
Maki Wakamiya ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Signaling Pathway ◽  
Functional Role ◽  
Vascular Endothelial Cells ◽  
Ectopic Expression ◽  
Intracellular Camp ◽  
Vascular Endothelial ◽  
Initial Adhesion

Introduction: Intracellular cAMP receptor exchange proteins directly activated by cAMP 1 (EPAC1) regulate obligate intracellular parasitic bacterium rickettsial adherence to and invasion into vascular endothelial cells (ECs). However, underlying precise mechanism(s) remain unclear. The aim of the study is to dissect the functional role of the EPAC1-ANXA2 signaling pathway during initial adhesion of rickettsiae to EC surfaces. Methods: In the present study, an established system that is anatomically based and quantifies bacterial adhesion to ECs in vivo was combined with novel fluidic force microscopy (FluidFM) to dissect the functional role of the EPAC1-ANXA2 signaling pathway in rickettsiae–EC adhesion. Results: The deletion of the EPAC1 gene impedes rickettsial binding to endothelium in vivo. Rickettsial OmpB shows a host EPAC1-dependent binding strength on the surface of a living brain microvascular EC (BMEC). Furthermore, ectopic expression of phosphodefective and phosphomimic mutants replacing tyrosine (Y) 23 of ANXA2 in ANXA2-knock out BMECs results in different binding force to reOmpB in response to the activation of EPAC1. Conclusions: EPAC1 modulates rickettsial adhesion, in association with Y23 phosphorylation of the binding receptor ANXA2. Underlying mechanism(s) should be further explored to delineate the accurate role of cAMP-EPAC system during rickettsial infection.

Abstract 438: Downregulation of Ca 2+ /calmodulin-dependent Protein Kinase Type II Delta in the Heart by Antisense Oligonucleotides Mitigates Development of Post-infarct Ventricular Arrhythmias

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Ting-yuan T Yeh ◽  
Xin Yi Yeap ◽  
Adam E Mullick
Keyword(s):  
Protein Kinase ◽  
Antisense Oligonucleotides ◽  
Ventricular Arrhythmias ◽  
Cardiac Mechanics ◽  
Type Ii ◽  
Dependent Protein Kinase ◽  
Dependent Protein ◽  
To Receive

Pathological activation of Ca2+/calmodulin-dependent protein kinase type II delta (CaMK2d) has been implicated in the development of heart failure (HF) and arrhythmia. In preclinical models, inhibition or deletion of cardiac CaMK2d has shown a benefit to prevent HF progression or arrhythmia occurrence. We hypothesized that reduction of CaMK2d in the heart by antisense oligonucleotides (ASO) can mitigate the inducibility of MI-associated ventricular arrhythmias. Eight-week-old female C57BL6/N mice, which received permanent ligation of the left anterior descending coronary artery, were randomized to receive PBS, control ASO or two different mouse CaMK2d ASOs five days after the surgery. The ASOs were administered subcutaneously at 50 mg/kg weekly for four weeks. At the end of study, programmed electrical stimulation (PES) was performed to evaluate ventricular effective refractory period (VERP) and inducibility of ventricular arrhythmias (VA). PCR results showed 70% reduction of cardiac CaMK2d in the CaMK2d ASO groups and no changes of other CaMK2 isoforms. There is no significant change of VERP (VERP expressed as mean±SEM, PBS: 35.2±3.0 ms, control ASO: 36.2±3.8 ms, CaMK2d ASO1: 35.7±2.3 ms and CaMK2d ASO2: 33.8±1.4 ms) while the inducible arrhythmias by PES are declined after CaMK2d ASO treatment (VA inducibility index expressed as mean±SEM, PBS: 1.21±0.27, control ASO: 1.21±0.52, CaMK2d ASO1: 0.54±0.22, CaMK2d ASO2: 0.47±0.22). Echocardiography and invasive hemodynamic studies were unable to demonstrate significant functional improvements in the CaMK2d ASO treated groups, suggesting that the anti-arrhythmia effects of CaMK2d ASO treatment were not secondary to improved cardiac mechanics. In conclusion, ASO-mediated reduction of cardiac CaMK2d in a murine MI model ameliorates MI-associated ventricular arrhythmias, providing in vivo proof-of-concept support of the pathological role of CaMK2d activity in MI-related arrhythmia.

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