TY - JOUR
T1 - Disruption of the actin cytoskeleton regulates cytokine-induced iNOS expression
AU - Zeng, Chenbo
AU - Morrison, Aubrey R.
PY - 2001
Y1 - 2001
N2 - Interleukin-1β (IL-1β) induces the inducible nitric oxide synthase (iNOS), resulting in the release of nitric oxide (NO) from glomerular mesangial cells. In this study, we demonstrated that disruption of F-actin formation by sequestration of G-actin with the toxin latrunculin B (LatB) dramatically potentiated IL-1β-induced iNOS protein expression in a dose-dependent manner. LatB by itself had little or no effect on iNOS expression. Staining of F-actin with nitrobenzoxadiazole (NBD)-phallacidin demonstrated that LatB significantly impaired F-actin stress fiber formation. Jasplakinolide (Jasp), which binds to and stabilizes F-actin, suppressed iNOS expression enhanced by LatB. These data strongly suggest that actin cytoskeletal dynamics regulates IL-1β-induced iNOS expression. We demonstrated that LatB decreases serum response factor (SRF) activity as determined by reporter gene assays, whereas Jasp increases SRF activity. The negative correlation between SRF activity and iNOS expression suggests a negative regulatory role for SRF in iNOS expression. Overexpression of a dominant negative mutant of SRF increases the IL-1β-induced iNOS expression, providing direct evidence that SRF inhibits iNOS expression.
AB - Interleukin-1β (IL-1β) induces the inducible nitric oxide synthase (iNOS), resulting in the release of nitric oxide (NO) from glomerular mesangial cells. In this study, we demonstrated that disruption of F-actin formation by sequestration of G-actin with the toxin latrunculin B (LatB) dramatically potentiated IL-1β-induced iNOS protein expression in a dose-dependent manner. LatB by itself had little or no effect on iNOS expression. Staining of F-actin with nitrobenzoxadiazole (NBD)-phallacidin demonstrated that LatB significantly impaired F-actin stress fiber formation. Jasplakinolide (Jasp), which binds to and stabilizes F-actin, suppressed iNOS expression enhanced by LatB. These data strongly suggest that actin cytoskeletal dynamics regulates IL-1β-induced iNOS expression. We demonstrated that LatB decreases serum response factor (SRF) activity as determined by reporter gene assays, whereas Jasp increases SRF activity. The negative correlation between SRF activity and iNOS expression suggests a negative regulatory role for SRF in iNOS expression. Overexpression of a dominant negative mutant of SRF increases the IL-1β-induced iNOS expression, providing direct evidence that SRF inhibits iNOS expression.
KW - Inducible nitric oxide synthase
KW - Jasplakinolide
KW - Latrunculin B
KW - Mesangial cell
KW - Serum response factor
UR - http://www.scopus.com/inward/record.url?scp=0034823919&partnerID=8YFLogxK
U2 - 10.1152/ajpcell.2001.281.3.c932
DO - 10.1152/ajpcell.2001.281.3.c932
M3 - Article
C2 - 11502570
AN - SCOPUS:0034823919
SN - 0363-6143
VL - 281
SP - C932-C940
JO - American Journal of Physiology - Cell Physiology
JF - American Journal of Physiology - Cell Physiology
IS - 3 50-3
ER -