Schwartz Margit, Böckmann Sabine, Borchert Philipp, Hinz Burkhard
Institute of Pharmacology and Toxicology, Rostock University Medical Center, Rostock, Germany.
Oncotarget. 2018 May 1;9(33):23149-23163. doi: 10.18632/oncotarget.25234.
Activation of the p38 mitogen-activated protein kinase (MAPK) pathway has been implicated in various detrimental events finally leading to endothelial dysfunction. The present study therefore investigates the impact of the p38 MAPK inhibitor SB202190 on the expression of the cytoprotective enzyme heme oxygenase-1 (HO-1) as well as metabolic activity, apoptosis and autophagy of endothelial cells. Using human umbilical vein endothelial cells (HUVEC) SB202190 was found to cause a time- and concentration-dependent induction of HO-1 protein. Induction of HO-1 protein expression was mimicked by SB203580, another p38 MAPK inhibitor, but not by SB202474, an inactive structural analogue of p38 MAPK inhibitors. HO-1 induction by both SB202190 and SB203580 was also demonstrated by analysis of mRNA expression. On the functional level, SB202190 was shown to increase metabolic activity and autophagy of HUVEC along with diminishing basal apoptosis. Treatment of cells with tin protoporphyrin IX (SnPPIX), a well-characterised HO-1 enzymatic inhibitor, or HO-1 siRNA left SB202190-modulated metabolic activity and autophagy virtually unaltered but caused a significant reversal of the anti-apoptotic action of SB202190. Conversely, however, HO-1 expression by SB202190 became completely suppressed by the autophagy inhibitor bafilomycin A. Bafilomycin A likewise fully reversed effects of SB202190 on metabolic activity and apoptosis, albeit significantly inducing apoptosis per se. Collectively, this work demonstrates SB202190 to confer upstream induction of autophagy followed by HO-1 induction resulting in potential protective effects against apoptosis. On the other hand, our data oppose HO-1 to contribute to SB202190-mediated increases in metabolic activity and autophagy, respectively.
p38丝裂原活化蛋白激酶（MAPK）通路的激活与各种有害事件有关，最终导致内皮功能障碍。因此，本研究调查了p38 MAPK抑制剂SB202190对细胞保护酶血红素加氧酶-1（HO-1）表达以及内皮细胞代谢活性、凋亡和自噬的影响。使用人脐静脉内皮细胞（HUVEC）发现，SB202190可引起HO-1蛋白的时间和浓度依赖性诱导。另一种p38 MAPK抑制剂SB203580可模拟HO-1蛋白表达的诱导，但p38 MAPK抑制剂的无活性结构类似物SB202474则不能。通过mRNA表达分析也证实了SB202190和SB203580对HO-1的诱导作用。在功能水平上，SB202190可增加HUVEC的代谢活性和自噬，同时减少基础凋亡。用锡原卟啉IX（SnPPIX，一种特征明确的HO-1酶抑制剂）或HO-1 siRNA处理细胞，几乎不会改变SB202190调节的代谢活性和自噬，但会显著逆转SB202190的抗凋亡作用。然而，相反地，自噬抑制剂巴弗洛霉素A可完全抑制SB202190诱导的HO-1表达。巴弗洛霉素A同样完全逆转了SB202190对代谢活性和凋亡的影响，尽管其本身会显著诱导凋亡。总的来说，这项研究表明SB202190可诱导自噬，随后诱导HO-1，从而对凋亡产生潜在的保护作用。另一方面，我们的数据表明HO-1分别对SB202190介导的代谢活性和自噬增加没有贡献。
