Synthetic bastadins modify the activity of ryanodine receptors in cultured cerebellar granule cells.
Although the interactions of several natural bastadins with the RyR1 isoform of the ryanodine receptor in sarcoplasmic reticulum has been described, their structure-dependent interference with the RyR2 isoform, mainly expressed in cardiac muscle and brain neurons, has not been studied. In this work, we examined calcium transients induced by natural bastadin 10 and several synthetic bastadins in cultured cerebellar granule cells known to contain RyR2. The fluorescent calcium indicator fluo-3 and confocal microscopy were used to evaluate changes in the intracellular Ca(2+) concentration (Ca(i)), and the involvement of ryanodine receptors was assessed using pharmacological tools. Our results demonstrate that apart from the inactive BAST218F6 (a bisdebromo analogue of bastadin 10), synthetic bastadin 5, and synthetic analogues BAST217B, BAST240 and BAST268 (at concentrations >20 microM) increased Ca(i) in a concentration-dependent, ryanodine- and FK-506-sensitive way, with a potency significantly exceeding that of 20 mM caffeine. Moreover, the same active bastadins at a concentration of 5 muM in the presence of ryanodine prevented a thapsigargin-induced increase in Ca(i). These results indicate that bastadins, acting in a structure-dependent manner, modify the activity of RyR2 in primary neuronal culture and provide new information about structure-related pharmacological properties of bastadins.
Zieminska
Elzbieta
E
Department of Neurochemistry, Medical Research Centre, Warsaw, Poland.
Stafiej
Aleksandra
A
Pitsinos
Emmanuel N
EN
Couladouros
Elias A
EA
Moutsos
Vassilios
V
Kozlowska
Hanna
H
Toczylowska
Beata
B
Lazarewicz
Jerzy W
JW
D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects*; D002531:Cerebellum / Q000166:cytology*; D055768:Halogenated Diphenyl Ethers; D015394:Molecular Structure; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D010456:Peptides, Cyclic; D010647:Phenyl Ethers / Q000138:chemical synthesis / Q000494:pharmacology*; D011161:Porifera / Q000737:chemistry; D051381:Rats; D017208:Rats, Wistar; D019837:Ryanodine Receptor Calcium Release Channel / Q000187:drug effects*; D016559:Tacrolimus / Q000494:pharmacology; D022021:Tacrolimus Binding Proteins / Q000378:metabolism; D019284:Thapsigargin / Q000494:pharmacology
D055768:Halogenated Diphenyl Ethers; D010456:Peptides, Cyclic; D010647:Phenyl Ethers; D019837:Ryanodine Receptor Calcium Release Channel; C094709:bastadin 10; D002110:Caffeine; D019284:Thapsigargin; C105188:bastadin 5; D022021:Tacrolimus Binding Proteins; D002118:Calcium; D016559:Tacrolimus