scholarly journals Downregulation of cGMP-dependent protein kinase-1 activity in the corpus cavernosum smooth muscle of diabetic rabbits

2004 ◽  
Vol 287 (4) ◽  
pp. R950-R960 ◽  
Author(s):  
Shaohua Chang ◽  
Joseph A. Hypolite ◽  
Marielena Velez ◽  
Arun Changolkar ◽  
Alan J. Wein ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase ◽  
Corpus Cavernosum ◽  
Effector Proteins ◽  
Smooth Muscle Relaxation ◽  
Diabetic Patients ◽  
Dependent Protein Kinase ◽  
Cgmp Dependent Protein Kinase ◽  
Dependent Protein

Increased guanosine 3′,5′-cyclic monophosphate (cGMP), induced by nitric oxide release, is crucial for corpus cavernosum smooth muscle (CCSM) relaxation within the penis. This CCSM relaxation (necessary for penile erection) is impaired in men with erectile dysfunction (ED), especially those men with diabetes. One of the effector proteins for cGMP is cGMP-dependent protein kinase-1 (PKG-1). PKG-1 knockout mice exhibit detrusor overactivity ( Am J Physiol Regul Integr Comp Physiol 279: R1112–R1120, 2000) and, more relevant to this study, ED ( Proc Natl Acad Sci USA 97: 2349–2354, 2000), suggesting an in vivo role for PKG-1 in urogenital smooth muscle relaxation. In the current study, using normal rabbit CCSM, Western blot analysis revealed high expression of PKG-1 at levels almost equivalent to aorta (previously shown to have high PKG-1 expression) and that the two known alternatively spliced isoforms of PKG-1 (α and β) are expressed in nearly equal amounts in the CCSM. However, in response to alloxan-induced diabetes, there was a decrease in expression of both PKG-1 isoforms at the mRNA and protein levels as determined by real-time RT-PCR and Western blotting, respectively, but with the PKG-1α isoform expression decreased to a greater extent. Moreover, diabetes was associated with significantly decreased PKG-1 activity of CCSM in vitro, correlating with decreased CCSM relaxation. Immunofluorescence microscopy revealed a diabetes-associated decrease in PKG-1 in the CCSM cells. In conclusion, our results demonstrate for the first time a significant downregulation of PKG-1 expression associated with decreased PKG-1 activity in the CCSM in response to diabetes. Furthermore, these results suggest a mechanistic basis for the decreased efficacy of phosphodiesterase V inhibitors in treating diabetic patients with ED.

Regulation of cGMP-induced relaxation and cGMP-dependent protein kinase in rat myometrium during pregnancy

1998 ◽  
Vol 274 (3) ◽  
pp. C748-C756 ◽  
Author(s):  
R. Ann Word ◽  
Trudy L. Cornwell
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase ◽  
Ovariectomized Rats ◽  
Smooth Muscle Relaxation ◽  
Dependent Protein Kinase ◽  
Pregnant Rats ◽  
Aortic Smooth Muscle ◽  
Cgmp Dependent Protein Kinase ◽  
Dependent Protein ◽  
High Concentrations

Increases in guanosine 3′,5′-cyclic monophosphate (cGMP) induced by nitric oxide (NO), nitrovasodilators, and atrial peptides correlate with relaxation of vascular smooth muscle. Relaxation of myometrial smooth muscle by increases in cGMP, however, has required unusually high concentrations of the cyclic nucleotide. We tested the hypothesis that the sensitivity of myometrium to relaxation by cGMP is increased during pregnancy. Aortic smooth muscle was more sensitive to relaxation by cGMP than myometrial tissues, and, contrary to our hypothesis, myometrium from pregnant rats was least sensitive. Although levels of cGMP were elevated after treatment with the NO donor, S-nitroso- N-acetylpenicillamine, relaxation of myometrial tissues obtained from pregnant rats occurred only at extraordinarily high concentrations. The levels of cGMP-dependent protein kinase (PKG) were significantly decreased in myometrium from pregnant rats compared with myometrium from nonpregnant cycling animals or aortic smooth muscle. Administration of estradiol to ovariectomized rats increased myometrial PKG expression, and progesterone antagonized this response. We conclude that 1) myometrial tissues from pregnant rats are not sensitive to relaxation by cGMP and 2) this insensitivity to cGMP is accompanied by progesterone-mediated decreases in the level of PKG expression.

Cyclic GMP-dependent protein kinase is required for thrombospondin and tenascin mediated focal adhesion disassembly

1996 ◽  
Vol 109 (10) ◽  
pp. 2499-2508 ◽  
Author(s):  
J.E. Murphy-Ullrich ◽  
M.A. Pallero ◽  
N. Boerth ◽  
J.A. Greenwood ◽  
T.M. Lincoln ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase ◽  
Focal Adhesion ◽  
Kinase Activity ◽  
Catalytic Domain ◽  
Focal Adhesions ◽  
Matrix Proteins ◽  
Dependent Protein Kinase ◽  
Cgmp Dependent Protein Kinase ◽  
Dependent Protein

Focal adhesions are specialized regions of cell membranes that are foci for the transmission of signals between the outside and the inside of the cell. Intracellular signaling events are important in the organization and stability of these structures. In previous work, we showed that the counter-adhesive extracellular matrix proteins, thrombospondin, tenascin, and SPARC, induce the disassembly of focal adhesion plaques and we identified the active regions of these proteins. In order to determine the mechanisms whereby the anti-adhesive matrix proteins modulate cytoskeletal organization and focal adhesion integrity, we examined the role of protein kinases in mediating the loss of focal adhesions by these proteins. Data from these studies show that cGMP-dependent protein kinase is necessary to mediate focal adhesion disassembly triggered by either thrombospondin or tenascin, but not by SPARC. In experiments using various protein kinase inhibitors, we observed that selective inhibitors of cyclic GMP-dependent protein kinase, KT5823 and Rp-8-Br-cGMPS, blocked the effects of both the active sequence of thrombospondin 1 (hep I) and the alternatively-spliced segment (TNfnA-D) of tenascin-C on focal adhesion disassembly. Moreover, early passage rat aortic smooth muscle cells which have high levels of cGMP-dependent protein kinase were sensitive to hep I treatment, in contrast to passaged cGMP-dependent protein kinase deficient cells which were refractory to hep I or TNfnA-D treatment, but were sensitive to SPARC. Transfection of passaged smooth muscle cells with the catalytic domain of PKG I alpha restored responsiveness to hep I and TNfnA-D. While these studies show that cGMP-dependent protein kinase activity is necessary for thrombospondin and tenascin-mediated focal adhesion disassembly, kinase activity alone is not sufficient to induce disassembly as transfection of the catalytic domain of the kinase in the absence of additional stimuli does not result in loss of focal adhesions.

Physiological concentration of atrial natriuretic peptide induces endothelial regeneration in vitro

2003 ◽  
Vol 284 (4) ◽  
pp. H1388-H1397 ◽  
Author(s):  
Hyun Kook ◽  
Hiroshi Itoh ◽  
Bong Seok Choi ◽  
Naoki Sawada ◽  
Kentaro Doi ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Protein Kinase ◽  
Dependent Protein Kinase ◽  
Physiological Concentration ◽  
Cell Numbers ◽  
Cgmp Dependent Protein Kinase ◽  
Dependent Protein ◽  
Regeneration In Vitro

Both nitric oxide (NO) and natriuretic peptides produce apoptosis of vascular smooth muscle cells. However, there is evidence that NO induces endothelial cell proliferation, which suggests that there is a difference in the response of endothelial cells to natriuretic peptides. The purpose of this study was to investigate the effect of atrial natriuretic peptide (ANP) on human endothelial cell survival. ANP within the physiological concentration (10−11mol/l) induced a 52% increase in the number of human coronary arterial endothelial cells and a 63% increase in human umbilical vein endothelial cells at a low concentration of serum. The increase in cell numbers was blocked by pretreatment with RP8-CPT-cGMP (RP8), a cGMP-dependent protein kinase inhibitor, with wortmannin, an Akt/PKB inhibitor, and with PD-98059, an ERK1/2 inhibitor. In a Transwell migration test, ANP also increased the cell migration, and RP8, wortmannin, and PD-98059 blocked this increase. A wound healing assay was performed to examine the effects of ANP on regeneration in vitro. ANP increased both cell numbers and migration, but the effects were blocked by the above three kinase inhibitors. ANP increased the expression of phospho-Akt and of phospho-ERK1/2 within 1.5 h. These results suggest that ANP can potentiate endothelial regeneration by cGMP-dependent protein kinase stimulation and subsequent Akt and ERK1/2 activations.

scholarly journals Regulation of vascular smooth muscle growth by cyclic nucleotides and cGMP-dependent protein kinase

2005 ◽  
Vol 5 (Suppl 1) ◽  
pp. P62 ◽  
Author(s):  
Pascal Weinmeister ◽  
Robert Lukowski ◽  
Stefan Linder ◽  
Wolfgang Erl ◽  
Richard Brandl ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase ◽  
Vascular Smooth Muscle ◽  
Cyclic Nucleotides ◽  
Muscle Growth ◽  
Dependent Protein Kinase ◽  
Cgmp Dependent Protein Kinase ◽  
Dependent Protein
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