|
- 积分
- 156
- 威望
- 156
- 包包
- 1330
|
Ischemia induces regulator of G protein signaling 2 (RGS2) protein; s1 S* o) @. ?
upregulation and enhances apoptosis in astrocytes: C4 l3 t: x: c" a X8 j; F! H
Mehari Endale,1* Sung Dae Kim,1* Whi Min Lee,1 Sangseop Kim,2 Kyoungho Suk,2 Jae Youl Cho,3
& \/ p2 |! @) B& {% [* T' QHwa Jin Park,4 Yadav Wagley,5 Suk Kim,6 Jae-Wook Oh,5 and Man Hee Rhee1
9 `" L0 F$ V8 I- k: K b6 J+ Q: v0 D" D5 j
Endale M, Kim SD, Lee WM, Kim S, Suk K, Cho JY, Park HJ,
% w7 m# Y5 X& G" S) EWagley Y, Kim S, Oh JW, Rhee MH. Ischemia induces regulator of G
9 S0 f! x4 r: d2 q$ _. R7 z+ Cprotein signaling 2 (RGS2) protein upregulation and enhances apoptosis
; I$ y) e! Q. Min astrocytes. Am J Physiol Cell Physiol 298: C611–C623, 2010. First
* E" D) S+ e0 n. }3 Wpublished December 23, 2009; doi:10.1152/ajpcell.00517.2008.—Regulator
, A3 Q$ ]* x, Y }of G protein signaling (RGS) family members, such as RGS2,
4 Z; y; J4 p# Kinteract with G subunits of heterotrimeric G proteins, accelerating
, A- t/ F4 U4 o2 v. D, sthe rate of GTP hydrolysis and attenuating the intracellular signaling
; d0 p9 a# d2 K! \triggered by the G protein-coupled receptor-ligand interaction.
! \# l# H5 M5 @" B! x2 h' oThey are also reported to regulate G protein-effector interactions
7 G1 |5 h! ^. _8 p+ J1 ], aand form multiprotein signaling complexes. Ischemic stress-induced
. r8 U4 T8 h1 B6 ^3 Qchanges in RGS2 expression have been described in astrocytes,4 y5 C% E V( K( L5 H
and these changes are associated with intracellular signaling
/ f2 T% X$ I) ^5 n2 E; ucascades, suggesting that RGS2 upregulation may be an important, T7 f' f2 H B+ V. P; E! ^
mechanism by which astrocytes may regulate RGS2 function in7 ^/ V" U- C' |; B1 T
response to physiological stress. However, information on the+ x' F( T/ B$ J+ G9 B& d
functional roles of stress-induced modulation of RGS2 protein( b0 n4 @* R; o. }( W* }
expression in astrocyte function is limited. We report the role of `# x R, Y! T! ]
ischemic stress in RGS2 protein expression in rat C6 astrocytoma
% O+ I+ u/ O5 S9 A+ Z% n& zcells and primary mouse astrocytes. A marked increase in RGS2
2 ~& e+ o+ {7 b" ?7 E5 Yoccurred after ischemic stress induced by chemicals (sodium azide
, z4 z( ~6 C, {, `8 p; x; tand 2-deoxyglucose) or oxygen-glucose deprivation (OGD, real
' J. a. v5 x! z- oischemia). RGS2 mRNA expression was markedly enhanced by 1
2 b# P) Z( R+ p/ k3 ~) z9 Sh of exposure to chemical ischemia or 6 h of OGD followed by 2& Q- Z; h! ]" w' E. ]% B7 \* A0 l5 w: O
or 6 h of recovery, respectively. This enhanced expression in
7 y. }$ i* k1 F% ]primary astrocytes and C6 cells was restored to baseline levels
* ^/ K e9 R+ q! S1 d( [# E! k( _after 12 h of recovery from chemically induced ischemic stress or! T s* d# c8 V# P& `6 M. j1 c/ k
4 – 6 h of recovery from OGD. RGS2 protein was also significantly
: M, T0 [! ` Uexpressed at 12–24 h of recovery from ischemic insult. Ischemiainduced
6 l9 i# i! U X6 v, ^RGS2 upregulation was associated with enhanced apoptosis.- n) T2 S- Z' c+ x8 B
It significantly increased annexin V-positive cells, cleaved
; z4 @- ^7 x$ }" S4 W+ S; X6 n7 Acaspase-3, and enhanced DNA ladder formation and cell cycle' @# G$ Q5 J& K2 F( M
arrest. However, a small interfering RNA (siRNA)-mediated RGS26 y' L8 Q- i D9 J( o9 E
knockdown reversed the apoptotic cell death associated with ischemia-
% h* X+ `5 l/ _6 \induced RGS2 upregulation. Upregulated RGS2 was significantly
8 e6 D* q4 D+ v! p6 p+ Jinhibited by SB-203580, a p38 MAPK inhibitor. Rottlerin,) R! K. j5 g7 M- G
a potent inhibitor of PKC, completely abrogated the increased6 E* e; R8 ?+ R' |0 @: @
RGS2 expression. We also examine whether ischemia-induced4 x1 a: }* l/ n" R
RGS2-mediated apoptosis is affected by siRNA-targeted endogenous9 Z7 O7 n3 ?* z
PKC downregulation or its phosphorylation. Although
1 `) } \) Y. }3 D' Q: f* u a3 R) ORGS2 upregulation was not affected, siRNA transfection significantly% E' H& U0 p3 S8 j! Z' ]( o
suppressed endogenous PKC mRNA and protein expresexpressions.
- p) L4 C! P5 M5 D( uIschemia-induced PKC phosphorylation and caspase-3' g. t- i8 f5 D3 d, |2 ^# F, {
cleavage were dose dependently inhibited by PKC knockdown,
) S- v9 T$ ?7 E+ @% a S, ]3 vand this endogenous PKC suppression reversed ischemia-induced
# Y$ p/ }) X6 }7 A# n' a" |4 qannexin V-positive cells. This study suggests that ischemic stress- `' n* a- ]- Y5 O8 x, Q
increases RGS2 expression and that this condition contributes to% r* X8 H- f8 z2 M
enhanced apoptosis in C6 cells and primary astrocytes. The signaling
0 Z! f4 _) Z* C3 Oit follows may involve PKC and p38 MAPK pathways.& [2 F+ D# j6 |8 h9 N
希望对你有用 |
附件: 你需要登录才可以下载或查看附件。没有帐号？注册
-
总评分: 威望 + 2
包包 + 5
查看全部评分
|
发表于 2011-8-24 05:41
