At the cross-point of connexins, calcium, and ATP: blocking hemichannels inhibits vasoconstriction of rat small mesenteric arteries

Autor: Bert Vanheel, Geert Bultynck, Elke Decrock, Benjamin Wacquier, Geneviève Dupont, Kelly Decaluwé, Johan Van de Voorde, Mélissa Bol, Luc Leybaert, Nan Wang, Marijke De Bock, Ashish A. Gadicherla, Harold V.M. van Rijen, Dmitri V. Krysko
Rok vydání: 2016
Předmět:
0301 basic medicine
P2Y receptor
Time Factors
Purinergic Antagonists
Physiology
Vasodilator Agents
Cell Communication
Connexins
Muscle
Smooth
Vascular
Norepinephrine
Adenosine Triphosphate
Inositol 1
4
5-Trisphosphate Receptors
Vasoconstrictor Agents
Mesenteric arteries
Mice
Knockout
Microscopy
Confocal
Models
Cardiovascular
Gap Junctions
Pannexin
Purinergic signalling
Mesenteric Arteries
Phenotype
medicine.anatomical_structure
cardiovascular system
Female
medicine.symptom
Cardiology and Cardiovascular Medicine
Blood vessel
medicine.medical_specialty
Genotype
Myocytes
Smooth Muscle
In Vitro Techniques
Biology
Contractility
03 medical and health sciences
Physiology (medical)
Internal medicine
medicine
Animals
Computer Simulation
Calcium Signaling
Rats
Wistar
030104 developmental biology
Endocrinology
Vasoconstriction
Connexin 43
Biophysics
Calcium
Peptides
Myograph
Zdroj: Cardiovascular Research. 113:195-206
ISSN: 1755-3245
0008-6363
Popis: Aims Connexins form gap-junctions (GJs) that directly connect cells, thereby coordinating vascular cell function and controlling vessel diameter and blood flow. GJs are composed of two hemichannels contributed by each of the connecting cells. Hemichannels also exist as non-junctional channels that, when open, lead to the entry/loss of ions and the escape of ATP. Here we investigated cross-talk between hemichannels and Ca2+/purinergic signaling in controlling blood vessel contraction. We hypothesized that hemichannel Ca2+ entry and ATP release contributes to smooth muscle cell (SMC) Ca2+ dynamics, thereby influencing vessel contractility. We applied several peptide modulators of hemichannel function and inhibitors of Ca2+ and ATP signaling to investigate their influence on SMC Ca2+ dynamics and vessel contractility. Methods and Results Confocal Ca2+ imaging studies on small mesenteric arteries (SMAs) from rat demonstrated that norepinephrine-induced SMC Ca2+ oscillations were inhibited by blocking IP3 receptors with xestospongin-C and by interfering with hemichannel function, most notably by the specific Cx43 hemichannel blocking peptide TAT-L2 and by TAT-CT9 that promotes Cx43 hemichannel opening. Evidence for hemichannel involvement in SMC function was supported by the fact that TAT-CT9 significantly increased SMC resting cytoplasmic Ca2+ concentration, indicating it facilitated Ca2+ entry, and by the observation that norepinephrine-triggered vessel ATP release was blocked by TAT-L2. Myograph tension measurements on isolated SMAs showed significant inhibition of norepinephrine-triggered contractility by the ATP receptor antagonist suramin, but the strongest effect was observed with TAT-L2 that gave ~80% inhibition at 37°C. TAT-L2 inhibition of vessel contraction was significantly reduced in conditional Cx43 KO animals, indicating the effect was Cx43 hemichannel-dependent. Computational modeling suggested these results could be explained by the opening of a single hemichannel per SMC. Conclusions These results indicate that Cx43 hemichannels contribute to SMC Ca2+ dynamics and contractility, by facilitating Ca2+ entry, ATP release and purinergic signaling.
Databáze: OpenAIRE
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