Identification of a new class of inhibitors of the voltage-gated potassium channel, Kv1.3, with immunosuppressant properties.
The voltage-gated potassium channel, K(v)1.3, is a novel target for development of immunosuppressants. Using a functional (86)Rb(+) efflux assay, a new class of high-affinity K(v)1.3 inhibitors has been identified. The initial active in this series, 4-phenyl-4-[3-(2-methoxyphenyl)-3-oxo-2-azaprop-1-yl]cyclohexanone (PAC), which is representative of a disubstituted cyclohexyl (DSC) template, displays a K(i) of ca. 300 nM and a Hill coefficient near 2 in the flux assay and in voltage clamp recordings of K(v)1.3 channels in human T-lymphocytes. PAC displays excellent specificity as it only blocks members of the K(v)1 family of potassium channels but does not affect many other types of ion channels, receptors, or enzyme systems. Block of K(v)1.3 by DSC analogues occurs with a well-defined structure-activity relationship. Substitution at the C-1 ketone of PAC generates trans (down) and cis (up) isomer pairs. Whereas many DSC derivatives do not display selectivity in their interaction with different K(v)1.x channels, trans DSC derivatives distinguish between K(v)1.x channels based on their rates of C-type inactivation. DSC analogues reversibly inhibit the Ca(2+)-dependent pathway of T cell activation in in vitro assays. Together, these data suggest that DSC derivatives represent a new class of immunosuppressant agents and that specific interactions of trans DSC analogues with channel conformations related to C-type inactivation may permit development of selective K(v)1.3 channel inhibitors useful for the safe treatment of autoimmune diseases.
Schmalhofer
William A
WA
Department of Ion Channels, Merck Research Laboratories, Rahway, New Jersey 07065, USA.
Bao
Jianming
J
McManus
Owen B
OB
Green
Brian
B
Matyskiela
Mary
M
Wunderler
Denise
D
Bugianesi
Randal M
RM
Felix
John P
JP
Hanner
Markus
M
Linde-Arias
Ana-Rosa
AR
Ponte
Cristiano G
CG
Velasco
Lucia
L
Koo
Gloria
G
Staruch
Mary Jo
MJ
Miao
Shouwu
S
Parsons
William H
WH
Rupprecht
Kathleen
K
Slaughter
Robert S
RS
Kaczorowski
Gregory J
GJ
Garcia
Maria L
ML
D000409:Alanine / Q000235:genetics; D000818:Animals; D001665:Binding Sites; D016466:CHO Cells; D002460:Cell Line; D006224:Cricetinae; D003512:Cyclohexanones / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D006168:Guinea Pigs; D006801:Humans; D007166:Immunosuppressive Agents / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D007424:Intracellular Fluid / Q000378:metabolism; D051664:Kv1.3 Potassium Channel; D008213:Lymphocyte Activation / Q000187:drug effects; D007470:Monoiodotyrosine / Q000378:metabolism; D018408:Patch-Clamp Techniques; D010649:Phenylalanine / Q000235:genetics; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000235:genetics / Q000378:metabolism; D024642:Potassium Channels, Voltage-Gated / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051381:Rats; D012604:Scorpion Venoms / Q000378:metabolism; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D014162:Transfection; D014315:Triterpenes / Q000378:metabolism; D014443:Tyrosine / Q000235:genetics
C460479:4-phenyl-4-(3-(2-methoxyphenyl)-3-oxo-2-azaprop-1-yl)cyclohexanone; D003512:Cyclohexanones; D007166:Immunosuppressive Agents; C496973:KCNA3 protein, human; C496975:Kcna3 protein, rat; D051664:Kv1.3 Potassium Channel; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D012604:Scorpion Venoms; D014315:Triterpenes; C118658:ditritiocorreolide; C110392:hongotoxin 1; D014443:Tyrosine; D010649:Phenylalanine; D007470:Monoiodotyrosine; D000409:Alanine