Withaferin A induces proteasome inhibition, endoplasmic reticulum stress, the heat shock response and acquisition of thermotolerance.
Withaferin A induces proteasome inhibition, endoplasmic reticulum stress, the heat shock response and acquisition of thermotolerance.
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DOI：
10.1371/journal.pone.0050547
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Heikkila JJ
中科院分区：
文献类型：
--
作者：
Khan S;Rammeloo AW;Heikkila JJ
在本研究中，withaferin A（WA），甾体内酯与抗炎和抗肿瘤的特性，抑制蛋白酶体活性和诱导内质网（ER）和细胞质HSP积累在非洲爪蟾A6肾上皮细胞。蛋白酶体抑制WA的泛素化蛋白的积累和糜蛋白酶样活性的下降。此外，免疫印迹分析显示，用WA处理细胞诱导HSP的积累，包括ER分子伴侣、BiP和GRP 94，以及细胞质/细胞核HSP、HSP 70和HSP 30。此外，WA诱导的蛋白激酶，Akt的相对水平的增加，而肌动蛋白的水平与对照组相比没有变化。北方印迹实验表明，WA诱导bip、hsp 70和hsp 30 mRNA的积累，但不诱导eIF-1α mRNA的积累。有趣的是，WA与轻度热休克协同作用，以提高HSP 70和HSP 30的积累在更大程度上比单独两种应激源的总和。使用BiP或GRP 94时没有观察到后一种现象。免疫细胞化学分析表明，WA诱导的BiP的积累主要发生在核周区域的点状图案，而HSP 30的积累主要发生在细胞质中的颗粒图案与一些染色在细胞核中。长时间暴露于WA导致F-肌动蛋白细胞骨架的解体以及产生与F-肌动蛋白共定位的相对较大的HSP 30染色结构。最后，之前暴露的细胞WA治疗，诱导热休克蛋白的积累赋予了热保护的状态，因为它保护F-肌动蛋白细胞骨架对随后的细胞毒性热挑战。
In the present study, withaferin A (WA), a steroidal lactone with anti-inflammatory and anti-tumor properties, inhibited proteasome activity and induced endoplasmic reticulum (ER) and cytoplasmic HSP accumulation in Xenopus laevis A6 kidney epithelial cells. Proteasomal inhibition by WA was indicated by an accumulation of ubiquitinated protein and a decrease in chymotrypsin-like activity. Additionally, immunoblot analysis revealed that treatment of cells with WA induced the accumulation of HSPs including ER chaperones, BiP and GRP94, as well as cytoplasmic/nuclear HSPs, HSP70 and HSP30. Furthermore, WA-induced an increase in the relative levels of the protein kinase, Akt, while the levels of actin were unchanged compared to control. Northern blot experiments determined that WA induced an accumulation in bip, hsp70 and hsp30 mRNA but not eIF-1α mRNA. Interestingly, WA acted synergistically with mild heat shock to enhance HSP70 and HSP30 accumulation to a greater extent than the sum of both stressors individually. This latter phenomenon was not observed with BiP or GRP94. Immunocytochemical analysis indicated that WA-induced BiP accumulation occurred mainly in the perinuclear region in a punctate pattern, while HSP30 accumulation occurred primarily in a granular pattern in the cytoplasm with some staining in the nucleus. Prolonged exposure to WA resulted in disorganization of the F-actin cytoskeleton as well as the production of relatively large HSP30 staining structures that co-localized with F-actin. Finally, prior exposure of cells to WA treatment, which induced the accumulation of HSPs conferred a state of thermal protection since it protected the F-actin cytoskeleton against a subsequent cytotoxic thermal challenge.
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DOI：
10.1083/jcb.143.7.1883
发表时间：
1998-12-28
期刊：
The Journal of cell biology
影响因子：
--
作者：
Johnston JA;Ward CL;Kopito RR
通讯作者：
Kopito RR
DOI：
10.1073/pnas.96.11.6137
发表时间：
1999-05-25
影响因子：
11.1
作者：
Bova, MP;Yaron, O;Horwitz, J
通讯作者：
Horwitz, J
影响因子：
3.7
作者：
Borm, B;Requardt, RP;Kirfel, G
通讯作者：
Kirfel, G
影响因子：
2.7
作者：
Haas, Kevin F.;Woodruff, Elvin;Broadie, Kendal
通讯作者：
Broadie, Kendal
影响因子：
3.5
作者：
KRONE, PH;SNOW, A;HEIKKILA, JJ
通讯作者：
HEIKKILA, JJ