Modulation of smooth muscle contraction by sphingosylphosphorylcholine

1995 ◽  
Vol 269 (3) ◽  
pp. G370-G377 ◽  
Author(s):  
K. N. Bitar ◽  
H. Yamada
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase ◽  
Smooth Muscle Cells ◽  
Map Kinase ◽  
Intracellular Signaling ◽  
Calcium Release ◽  
Muscle Cells ◽  
Smooth Muscle Contraction ◽  
Mitogen Activated Protein Kinase ◽  
Maximal Response

We have investigated the effect of sphingosylphosphorylcholine (SPC), a synthetic product that was implicated in the sphingomyelin cycle, and have assessed its role in intracellular signaling. SPC induced a dose-dependent contractile effect of smooth muscle cells isolated from the rectosigmoid of the rabbit. Maximal contraction occurred at 10(-6) M. The response started early, 25.4 +/- 6% shortening at 15 s, peaked at 30 s (32.5 +/- 2%), and remained sustained at 8 min (30.0 +/- 3.5%). Preincubation of the cells with thapsigargin had no effect on contraction induced by SPC. The response to a combination of threshold concentrations of inositol 1,4,5-trisphosphate (IP3) and SPC was additive and was significantly different from the maximal response elicited by each agent alone. SPC also induced activation of mitogen-activated protein kinase (MAP kinase). This study demonstrates that SPC is important in cellular signaling of gastrointestinal smooth muscle cells through a mechanism that is independent of IP3-sensitive calcium release and probably through activation of a protein kinase C-mediated activation of MAP kinase.

scholarly journals N-terminal pyroglutamate formation in CX3CL1 is essential for its full biologic activity

2017 ◽  
Vol 37 (4) ◽  
Author(s):  
Astrid Kehlen ◽  
Monique Haegele ◽  
Livia Böhme ◽  
Holger Cynis ◽  
Torsten Hoffmann ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase ◽  
Smooth Muscle Cells ◽  
Adhesion Molecule ◽  
Muscle Cells ◽  
Mitogen Activated Protein Kinase ◽  
Intercellular Adhesion Molecule ◽  
Dependent Manner ◽  
Glutaminyl Cyclase ◽  
N Terminus

CX3CL1 (fractalkine) is a unique member of the CX3C chemokine family and mediates both adhesion and cell migration in inflammatory processes. Frequently, the activity of chemokines depends on a modified N-terminus as described for the N-terminus of CCL2 modified to a pGlu- (pyroglutamate) residue by QC (glutaminyl cyclase) activity. Here, we assess the role of the pGlu-modified residue of the CX3CL1 chemokine domain in human endothelial and smooth muscle cells. For the first time, we demonstrated using MS that QC (QPCT, gene name of QC) or its isoenzyme isoQC (iso-glutaminyl cyclase) (QPCTL, gene name of isoQC) catalyse the formation of N-terminal-modified pGlu-CX3CL1. Expression of QPCT is co-regulated with its substrates CCL2 and CX3CL1 in HUVECs (human umbilical vein endothelial cells) and HCASMCs (human coronary artery smooth muscle cells) upon stimulation with TNF-α and IL-1β whereas QPCTL expression is not affected. By contrast, inhibition of the NF-κB pathway using an IKK2 inhibitor decreased the expression of the co-regulated targets QPCT, CCL2, and CX3CL1. Furthermore, RNAi-mediated inhibition of QPCT expression resulted in a reduction in CCL2 and CX3CL1 mRNA. In HCASMCs, N-terminal-modified pGlu1-CX3CL1 induced a significant stronger effect on phosphorylation of ERK (extracellular signal regulated kinase) 1/2, Akt (protein kinase B), and p38 (p38 mitogen-activated protein kinase) kinases than the immature Gln1-CX3CL1 in a time- and concentration-dependent manner. Furthermore, pGlu1-CX3CL1 affected the expression of CCL2, CX3CL1, and the adhesion molecule ICAM1/CD54 (intercellular adhesion molecule-1) inducing in higher expression level compared with its Gln1-variant in both HCASMCs and HUVECs. These results strongly suggest that QC-catalysed N-terminal pGlu formation of CX3CL1 is important for the stability or the interaction with its receptor and opens new insights into the function of QC in inflammation.

Signal transduction pathways of IL-1β-mediated iNOS in pulmonary vascular smooth muscle cells

2001 ◽  
Vol 281 (4) ◽  
pp. L816-L823 ◽  
Author(s):  
Jonathan D. Finder ◽  
Jennifer L. Petrus ◽  
Andrew Hamilton ◽  
Raphael T. Villavicencio ◽  
Bruce R. Pitt ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase ◽  
Pulmonary Artery ◽  
Smooth Muscle Cells ◽  
Intracellular Signaling ◽  
Muscle Cells ◽  
Dominant Negative ◽  
Janus Kinase ◽  
Dominant Negative Mutant ◽  
Pulmonary Artery Smooth Muscle

Interleukin (IL)-1β is an important early mediator of inflammation in pulmonary artery smooth muscle cells. We previously reported that a geranylgeranyltransferase inhibitor elevated basal levels of inducible nitric oxide synthase (iNOS) and enhanced IL-1β-mediated induction, suggesting that Rac or Rho small G proteins are candidates for antagonism of such induction. In this study, overexpression of constitutively active Rac1 or its dominant negative mutant did not affect IL-1β induction of iNOS. Alternatively, treatment with Clostridium botulinum C3 exoenzyme, which ADP-ribosylates Rho, was associated with superinduction of iNOS, suggesting an inhibitory role for Rho. IL-1β activated the three mitogen-activated protein kinase (extracellular signal-regulated kinases 1 and 2, c-Jun NH2-terminal kinase/stress-activated protein kinase, and p38) and the Janus kinase (JAK)-signal transducer and activator of transcription pathways. The former two pathways were not associated with IL-1β-mediated iNOS induction, whereas the latter two appeared to have inhibitory roles in iNOS expression. These data suggest that a broad intracellular signaling response to IL-1β in rat pulmonary artery smooth muscle cells results in elevated levels of iNOS that is opposed by the geranylgeranylated small G protein Rho as well as the p38 and JAK2 pathways.

Regulation of glucose transport in aortic smooth muscle cells by cAMP and cGMP

2001 ◽  
Vol 353 (3) ◽  
pp. 513-519 ◽  
Author(s):  
Christopher J. MacKENZIE ◽  
Jill M. WAKEFIELD ◽  
Fiona CAIRNS ◽  
Anna F. DOMINICZAK ◽  
Gwyn W. GOULD
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase ◽  
Smooth Muscle Cells ◽  
Primary Cultures ◽  
Muscle Cells ◽  
Mek Inhibitor ◽  
Mitogen Activated Protein Kinase ◽  
Common Element ◽  
Dependent Manner ◽  
Concentration Dependent Manner

We have studied the ability of cGMP and cAMP to modulate platelet-derived growth factor (PDGF)-stimulated 2-deoxy-d-glucose (deGlc) transport in primary cultures of vascular smooth muscle cells (VMSC) from rat aorta. PDGF stimulated deGlc transport in a time- and concentration-dependent manner. 8-Bromo-cGMP and atrial natriuretic peptide(1–28) [ANP(1–28)] were found to reduce PDGF-stimulated deGlc transport without affecting basal (unstimulated) transport activity. In contrast, 8-bromo-cAMP and dibutyryl-cAMP stimulated basal deGlc transport 2-fold and were without effect on PDGF-stimulated deGlc transport. 8-Bromo-cGMP also inhibited 8-bromo-cAMP-stimulated deGlc transport. The stimulation of deGlc transport by PDGF was sensitive to the mitogen-activated protein kinase (MAPK)/extracellular-signal-regulated kinase (ERK) kinase (MEK) inhibitor PD98059, and we show that ERK1/2 was activated by PDGF. Neither 8-bromo-cGMP nor ANP(1–28) inhibited PDGF-stimulated ERK activation, suggesting that the effects of cGMP and ANP(1–28) were not mediated by inhibition of this kinase. Our data also argue against a role for cGMP-dependent protein kinase in mediating the effects of cGMP or ANP(1–28). Collectively, our data suggest that in VSMC: (i) cGMP and cAMP have opposing effects on deGlc transport; (ii) PDGF and cAMP have common elements in the pathways by which they activate deGlc transport; and (iii) a common element may be the target of the cGMP-mediated inhibition of deGlc transport.

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