Downregulation of profilin with antisense oligodeoxynucleotides inhibits force development during stimulation of smooth muscle.
The actin-regulatory protein profilin has been shown to regulate the actin cytoskeleton and the motility of nonmuscle cells. To test the hypothesis that profilin plays a role in regulating smooth muscle contraction, profilin antisense or sense oligodeoxynucleotides were introduced into the canine carotid smooth muscle by a method of reversible permeabilization, and these strips were incubated for 2 days for protein downregulation. The treatment of smooth muscle strips with profilin antisense oligodeoxynucleotides inhibited the expression of profilin; it did not influence the expression of actin, myosin heavy chain, and metavinculin/vinculin. Profilin sense did not affect the expression of these proteins in smooth muscle tissues. Force generation in response to stimulation with norepinephrine or KCl was significantly lower in profilin antisense-treated muscle strips than in profilin sense-treated strips or in muscle strips not treated with oligodeoxynucleotides. The depletion of profilin did not attenuate increases in phosphorylation of the 20-kDa regulatory light chain of myosin (MLC20) in response to stimulation with norepinephrine or KCl. The increase in F-actin/G-actin ratio during contractile stimulation was significantly inhibited in profilin-deficient smooth muscle strips. These results suggest that profilin is a necessary molecule of signaling cascades that regulate carotid smooth muscle contraction, but that it does not modulate MLC20 phosphorylation during contractile stimulation. Profilin may play a role in the regulation of actin polymerization or organization in response to contractile stimulation of smooth muscle.
Tang
Dale D
DD
Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Dr., Indianapolis, IN 46202, USA. dtang@iupui.edu
Tan
Jian
J
D000199:Actins / Q000037:antagonists & inhibitors / Q000378:metabolism; D000818:Animals; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002339:Carotid Arteries; D003285:Contractile Proteins; D004285:Dogs; D015536:Down-Regulation; D066298:In Vitro Techniques; D008840:Microfilament Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D018994:Myosin Light Chains / Q000378:metabolism; D009638:Norepinephrine / Q000494:pharmacology; D020319:Oligodeoxyribonucleotides, Antisense / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011108:Polymers / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D051304:Profilins; D013844:Thiazoles / Q000494:pharmacology; D053778:Thiazolidines; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology*
D000199:Actins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D003285:Contractile Proteins; D008840:Microfilament Proteins; D018994:Myosin Light Chains; D020319:Oligodeoxyribonucleotides, Antisense; D011108:Polymers; D051304:Profilins; D013844:Thiazoles; D053778:Thiazolidines; D011189:Potassium Chloride; C037067:latrunculin A; D009638:Norepinephrine