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BioAssay: AID 1843

Summary of probe development for inhibitors/blockers of inward-rectifying potassium ion channel Kir2.1

Assay Implementation: Meng Wu Ph.D., Hao-ran Wang Ph.D., Haibo Yu Ph.D., Elena Makhina Ph.D., Jia Xu Ph.D., Eric S Dawson Ph.D., Corey R Hopkins Ph.D., Craig W Lindsley Ph.D., Owen B McManus Ph.D., and Min Li Ph.D.. ..more
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 Tested Compounds
 Tested Compounds
All(2)
 
 
Probe(2)
 
 
Active(2)
 
 
 Tested Substances
 Tested Substances
All(3)
 
 
Probe(3)
 
 
Active(3)
 
 
AID: 1843
Data Source: Johns Hopkins Ion Channel Center (Kir2.1_summary_1)
BioAssay Type: Summary, Candidate Probes/Leads with Supporting Evidence
Depositor Category: NIH Molecular Libraries Probe Production Network
BioAssay Version:
Deposit Date: 2009-07-01
Modify Date: 2013-03-27

Data Table ( Complete ):           Active    All
Target
Sequence: potassium inwardly-rectifying channel J2 [Mus musculus]
Description ..   
Protein Family: Inward rectifier potassium channel

Gene:KCNJ2     Related Protein 3D Structures     More BioActivity Data..
BioActive Compounds: Chemical Probe: 2    Active: 2
Depositor Specified Assays
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AIDNameTypeComment
1672Primary cell-based high-throughput screening assay for identification of compounds that inhibit/block inward-rectifying potassium ion channel Kir2.1screeningPrimary HTS of 305616 compounds where 2592 were identified as active.
2032Confirmatory screen for compounds that inhibit/block inward-rectifying potassium ion channel Kir2.1screeningConfirmatory screen of 2265 compounds in duplicates, and 927 are active.
2105Counter screen for compounds that inhibit/block inward-rectifying potassium ion channel Kir2.1screeningCounter Screen of the same 2265 compounds against parental HEK293 cell, and 426 are found to be active.
2236hERG counter screen for compounds that inhibit/block inward-rectifying potassium ion channel Kir2.1screeningCounter screen of 320 compounds against hERG channel, and 74 are found active.
2329KCNK9 specificity screen for compounds that inhibit/block inward-rectifying potassium ion channel Kir2.1screeningCounter screen of 320 compounds against KCNK9 channel, and 13 are found active.
2404Manual electrophysiological patch clamp assay and ROMK specificity of compounds that inhibit/block inward-rectifying potassium ion channel Kir2.1confirmatoryManual patch clamp CRC assay for 1 active compound against Kir2.1 and RomK channels.
2581Automated electrophysiology assay of compounds that inhibit/block inward-rectifying potassium ion channel Kir2.1confirmatoryAutomated electrophysiology CRC assay for 44 compounds, and 31 are active.
2591Manual electrophysiological patch clamp assay for SAR compounds that inhibit/block inward-rectifying potassium ion channel Kir2.1confirmatoryManual electrophysiological patch clamp CRC assay for 10 active compounds that inhibit Kir2.1
2594Confirmation dose response assay for compounds that inhibit/block inward-rectifying potassium ion channel Kir2.1confirmatoryDosage response assay for 25 compounds that inhibit Kir2.1, of which 22 are found active.
2345Specificity screen against Kir2.1 for compounds that potentiate KCNQ2screeningKCNQ2 potentiator Counter screen assay against Kir2.1 potassium channel for 1189 compounds and 18 are active.
463252Secondary automated electrophysiology assay of compounds that inhibit/block inward-rectifying potassium ion channel Kir2.1otherSecondary automated electrophysiology assay of compounds that inhibit/block inward-rectifying potassium ion channel Kir2.1##
504555Dose response assay on hERG potassium channel for Kir2.1 inhibitors on automated electrophysiologyconfirmatoryDose response assay on hERG potassium channel for Kir2.1 inhibitors on automated electrophysiology
504557Confirmation dose response assay for SAR compounds that inhibit/block inward-rectifying potassium ion channel Kir2.1.confirmatoryConfirmation dose response assay for SAR compounds that inhibit/block inward-rectifying potassium ion channel Kir2.1.
504559Dose response assay for compounds that inhibit inward-rectifying potassium channel Kir2.1 on automated electrophysiologyconfirmatoryDose response assay for compounds that inhibit inward-rectifying potassium channel Kir2.1 on automated electrophysiology
504828Manual electrophysiological patch clamp assay for extended SAR compounds that inhibit/block inward-rectifying potassium ion channel Kir2.1_1confirmatoryManual electrophysiological patch clamp assay for extended SAR compounds that inhibit/block inward-rectifying potassium ion channel Kir2.1_1
504693Dose response assay on hERG potassium channel for Kir2.1 inhibitors on automated electrophysiology (II)confirmatory
504694Dose response assay for compounds that inhibit inward-rectifying potassium channel Kir2.1 on automated electrophysiology (II)confirmatory
504695Confirmation dose response assay for SAR compounds that inhibit/block inward-rectifying potassium ion channel Kir2.1 (II)confirmatory
Description:
Source (MLPCN Center Name): Johns Hopkins Ion Channel Center (JHICC)
Center Affiliation: Johns Hopkins University, School of Medicine
Screening Center PI: Min Li, Ph.D.
Assay Provider: Elena Makhina Ph.D., University of Pittsburgh
Network: Molecular Libraries Probe Production Centers Network (MLPCN)
Grant Proposal Number: 1 R03 DA026212-01
Grant Proposal PI: Elena Makhina Ph.D., University of Pittsburgh
Assay Implementation: Meng Wu Ph.D., Hao-ran Wang Ph.D., Haibo Yu Ph.D., Elena Makhina Ph.D., Jia Xu Ph.D., Eric S Dawson Ph.D., Corey R Hopkins Ph.D., Craig W Lindsley Ph.D., Owen B McManus Ph.D., and Min Li Ph.D..



Name: Summary of probe development for inhibitors/blockers of inward-rectifying potassium ion channel Kir2.1


Description:

Potassium (K+) channels are well recognized as a target in the treatment of cardiovascular, neurological, renal and metabolic disorders [1, 2]. However, the number of ion channel drugs is strikingly small, compared to the number of ion channel genes. Most of the known K+ channel modulators lack potency and specificity. The reason for slow development of K+ channel drugs lies largely in the low capacity and high cost of electrophysiology-based screening techniques.

The overall goal of the project is to discover inhibitors of the Kir2.1 channel with EC50 < 1 uM. Identified compounds will serve as both a basis for development of clinical K+ channel drugs, and as a basic study of K+ channel physiology with novel mechanisms of action.

The Kir2.1 channel (KCNJ2) is a member of inwardly-rectifying potassium channels, expressing two transmembrane-spanning segments, flanking a conserved pore region. Inward rectifier K+ channels pass prominent inward currents, and mediate the cardiac inwardly-rectifying potassium current (IK1) [3], while outward currents are largely blocked. The rectification process is mediated through blocking of the channel pore by intracellular Mg2+ and polyamines, and is specific for individual Kir subtypes [4, 5]. Specific modulators of the Kir2.1 channel serve as leads for development of anti-arrhythmic drugs, including drugs for treatment of short- and long-QT syndromes, as well as for the treatment of Andersen syndrome. Several Kir2.1 inhibitor candidates have been discovered [6] [7], i.e. Chlorpromazine, Celastrol, and Gambogic acid. However, a highly specific, high potency small molecule is still in need, not only for the mechanistic probing of the ion channel activities, but also to generate leads for therapeutics for related diseases.

This BioAssay summarize the efforts of developing small molecular inhibitors to the inward-rectifying potassium ion channel Kir2.1.

References:

1. Kaczorowski, G.J., et al., Ion Channels as Drug Targets: The Next GPCRs. J. Gen. Physiol., 2008. 131(5): p. 399-405. PMID: 18411331
2. Garcia, M.L. and G.J. Kaczorowski, Potassium Channels as Targets for Therapeutic Intervention. Sci. STKE, 2005. 2005(302): p. pe46-. PMID: 16174819
3. Lopatin, A.N. and C.G. Nichols, Inward Rectifiers in the Heart: An Update on IK1. Journal of Molecular and Cellular Cardiology, 2001. 33(4): p. 625-638. PMID: 11273717
4. Ficker, E., et al., Spermine and spermidine as gating molecules for inward rectifier K+ channels. Science, 1994. 266(5187): p. 1068-1072. PMID: 7973666
5. Dhamoon, A.S., et al., Unique Kir2.x Properties Determine Regional and Species Differences in the Cardiac Inward Rectifier K+ Current. Circ Res, 2004. 94(10): p. 1332-1339. PMID: 15087421
6. Sun, H., et al., Chronic Inhibition of Cardiac Kir2.1 and hERG Potassium Channels by Celastrol with Dual Effects on Both Ion Conductivity and Protein Trafficking. J. Biol. Chem., 2006. 281(9): p. 5877-5884. PMID: 16407206
7. Zaks-Makhina, E., et al., Novel Neuroprotective K+ Channel Inhibitor Identified by High-Throughput Screening in Yeast. Mol Pharmacol, 2004. 65(1): p. 214-219. PMID: 14722253
Protocol
Please see the related BioAssays (i.e. AID 1672) for details of the assay protocol.

For the probes, the activity score is assigned as 100.
Comment
Result of this screening campaign has yielded a probe compound, ML133.
Result Definitions
TIDNameDescriptionHistogramTypeUnit
OutcomeThe BioAssay activity outcomeOutcome
ScoreThe BioAssay activity ranking scoreInteger
1ML#Molecular library probe numberString
Additional Information
Grant Number: 1 R03 DA026212-01

Data Table (Concise)
Classification
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