Postischemic deactivation of cardiac aldose reductase: role of glutathione S-transferase P and glutaredoxin in regeneration of reduced thiols from sulfenic acids.
Aldose reductase (AR) is a multifunctional enzyme that catalyzes the reduction of glucose and lipid peroxidation-derived aldehydes. During myocardial ischemia, the activity of AR is increased due to the oxidation of its cysteine residues to sulfenic acids. It is not known, however, whether the activated, sulfenic form of the protein (AR-SOH) is converted back to its reduced, unactivated state (AR-SH). We report here that in perfused mouse hearts activation of AR during 15 min of global ischemia is completely reversed by 30 min of reperfusion. During reperfusion, AR-SOH was converted to a mixed disulfide (AR-SSG). Deactivation of AR and the appearance of AR-SSG during reperfusion were delayed in hearts of mice lacking glutathione S-transferase P (GSTP). In vitro, GSTP accelerated glutathiolation and inactivation of AR-SOH. Reduction of AR-SSG to AR-SH was facilitated by glutaredoxin (GRX). Ischemic activation of AR was increased in GRX-null hearts but was attenuated in the hearts of cardiospecific GRX transgenic mice. Incubation of AR-SSG with GRX led to the regeneration of the reduced form of the enzyme. In ischemic cardiospecific AR transgenic hearts, AR was co-immunoprecipitated with GSTP, whereas in reperfused hearts, the association of AR with GRX was increased. These findings suggest that upon reperfusion of the ischemic heart AR-SOH is converted to AR-SSG via GSTP-assisted glutathiolation. AR-SSG is then reduced by GRX to AR-SH. Sequential catalysis by GSTP and GRX may be a general redox switching mechanism that regulates the reduction of protein sulfenic acids to cysteines.
Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky 40202, USA.
Karin
K
Wetzelberger
Shahid P
SP
Baba
Mahesh
M
Thirunavukkarasu
Ye-Shih
YS
Ho
Nilanjana
N
Maulik
Oleg A
OA
Barski
Daniel J
DJ
Conklin
Aruni
A
Bhatnagar
D000449:Aldehyde Reductase / Q000378:metabolism; D000818:Animals; D003545:Cysteine / Q000378:metabolism; D054477:Glutaredoxins / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D017202:Myocardial Ischemia / Q000201:enzymology / Q000378:metabolism*; D010084:Oxidation-Reduction; D013434:Sulfenic Acids / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000378:metabolism*
D054477:Glutaredoxins; D013434:Sulfenic Acids; D013438:Sulfhydryl Compounds; D000449:Aldehyde Reductase; D005982:Glutathione Transferase; D003545:Cysteine