TY - JOUR
T1 - The immunosuppressive and toxic effects of FK-506 are mechanistically related
T2 - Pharmacology of a novel antagonist of FK-506 and rapamycin
AU - Dumont, Francis J.
AU - Staruch, Mary Jo
AU - Koprak, Samuel L.
AU - Siekierka, John J.
AU - Lin, C. Shirley
AU - Harrison, Richard
AU - Sewell, Tonya
AU - Kindt, Victoria M.
AU - Beattie, Thomas R.
AU - Wyvratt, Matthew
AU - Sigal, Nolan H.
PY - 1992/9/1
Y1 - 1992/9/1
N2 - FK-506 inhibits Ca2+-dependent transcription of lymphokine genes in T cells, and thereby acts as a powerful immunosuppressant. However, its potential therapeutic applications may be seriously limited by several side effects, including nephrotoxicity and neurotoxicity. At present, it is unclear whether these immunosuppressive and toxic effects result from interference with related biochemical processes. FK-506 is known to interact with FK-binding protein-12 (FKBP-12), an abundant cytosolic protein with cis-trans peptidyl-prolyl isomerase activity (PPIase) activity. Because rapamycin (RAP) similarly binds to FKBP-12, although it acts in a manner different from FK-506, by inhibiting T cell responses to lymphokines, such an interaction with FKBP-12 is not sufficient to mediate immunosuppression. Recently, it was found that the complex of FKBP-12 with FK-506, but not with RAP, inhibits the phosphatase activity of calcineurin. Here, we used L-685,818, the C18-hydroxy, C21-ethyl derivative of FK-506, to explore further the role of FKBP-12 in the immunosuppressive and toxic actions of FK-506. Although L-685,818 bound with high affinity to FKBP-12 and inhibited its PPIase activity, it did not suppress T cell activation, and, when complexed with FKBP-12, did not affect calcineurin phosphatase activity. However, L-685,818 was a potent antagonist of the immunosuppressive activity of both FK-506 and RAP. Moreover, L-685,818 did not induce any toxicity in dogs and rats or in a mouse model of acute FK-506 nephrotoxicity, but it blocked the effect of FK-506 in this model. Therefore, FK-506 toxicity involves the disruption of biochemical mechanisms related to those implicated in T cell activation. Like immunosuppression, this toxicity is not due to the inhibition of the PPIase activity of FKBP-12, but may be linked to the inhibition of the phosphatase activity of calcineurin by the drug FKBP-12 complex.
AB - FK-506 inhibits Ca2+-dependent transcription of lymphokine genes in T cells, and thereby acts as a powerful immunosuppressant. However, its potential therapeutic applications may be seriously limited by several side effects, including nephrotoxicity and neurotoxicity. At present, it is unclear whether these immunosuppressive and toxic effects result from interference with related biochemical processes. FK-506 is known to interact with FK-binding protein-12 (FKBP-12), an abundant cytosolic protein with cis-trans peptidyl-prolyl isomerase activity (PPIase) activity. Because rapamycin (RAP) similarly binds to FKBP-12, although it acts in a manner different from FK-506, by inhibiting T cell responses to lymphokines, such an interaction with FKBP-12 is not sufficient to mediate immunosuppression. Recently, it was found that the complex of FKBP-12 with FK-506, but not with RAP, inhibits the phosphatase activity of calcineurin. Here, we used L-685,818, the C18-hydroxy, C21-ethyl derivative of FK-506, to explore further the role of FKBP-12 in the immunosuppressive and toxic actions of FK-506. Although L-685,818 bound with high affinity to FKBP-12 and inhibited its PPIase activity, it did not suppress T cell activation, and, when complexed with FKBP-12, did not affect calcineurin phosphatase activity. However, L-685,818 was a potent antagonist of the immunosuppressive activity of both FK-506 and RAP. Moreover, L-685,818 did not induce any toxicity in dogs and rats or in a mouse model of acute FK-506 nephrotoxicity, but it blocked the effect of FK-506 in this model. Therefore, FK-506 toxicity involves the disruption of biochemical mechanisms related to those implicated in T cell activation. Like immunosuppression, this toxicity is not due to the inhibition of the PPIase activity of FKBP-12, but may be linked to the inhibition of the phosphatase activity of calcineurin by the drug FKBP-12 complex.
UR - http://www.scopus.com/inward/record.url?scp=0026768730&partnerID=8YFLogxK
M3 - Article
C2 - 1380976
AN - SCOPUS:0026768730
SN - 0022-1007
VL - 176
SP - 751
EP - 760
JO - Journal of Experimental Medicine
JF - Journal of Experimental Medicine
IS - 3
ER -