Curtis Brenda J, Shults Jill A, Ramirez Luis, Kovacs Elizabeth J
From the Department of Surgery, Burn and Shock Trauma Research Institute, Loyola University Chicago, Stritch School of Medicine, Maywood, Illinois.
J Burn Care Res. 2016 Sep-Oct;37(5):321-7. doi: 10.1097/BCR.0000000000000318.
Dermal burn injury causes profound physiological derangements. Respiratory failure is a primary cause of morbidity and mortality after burn injury, in part, because of excessive and prolonged release of local and systemic proinflammatory mediators. Clinical and preclinical evidence suggests histone deacetylases (HDACs) are key mediators of inflammatory responses. The study objective was to explore the effects of dermal burn injury on pulmonary HDAC activity, identify specific lung HDAC(s) altered by burn, and characterize histone lysine acetylation status. Mice were subjected to a 15% total body surface area scald burn or a sham injury and euthanized 24 hours later. Whole lungs were harvested, or alveolar macrophages were isolated from bronchoalveolar lavage fluid. HDAC specific activity assays were performed, Western blots were run to analyze HDACs1, 2, 3, 4, and 10 or histone lysine acetylation levels, and HDAC1 and phosphorylated-HDAC1 levels and localization were examined by immunofluorescence. Burned mice had higher HDAC specific activity and increased HDAC1 levels compared with controls, but levels of other HDACs were comparable between groups. Burn injury increased levels of HDAC1 and phosphorylated-HDAC1 in bronchioles and alveolar sacs and was associated with global and specific diminished levels of histone H3 and histone H4 lysine acetylation. Our analyses reveal that pulmonary inflammation after burn injury may be modulated by epigenetic mechanisms involving HDACs because HDAC activity, HDAC1 expression and activity, and downstream histone acetylation were all altered after burn. Future studies will explore the role of HDAC inhibitors in reversing inflammatory defects and may ultimately lead to new treatment interventions for burn patients.
皮肤烧伤会导致严重的生理紊乱。呼吸衰竭是烧伤后发病和死亡的主要原因，部分原因是局部和全身促炎介质的过度且持续释放。临床和临床前证据表明，组蛋白去乙酰化酶（HDACs）是炎症反应的关键介质。本研究的目的是探讨皮肤烧伤对肺HDAC活性的影响，确定烧伤后发生改变的特定肺HDAC，并表征组蛋白赖氨酸乙酰化状态。将小鼠进行15%体表面积的烫伤或假手术损伤，并在24小时后实施安乐死。采集全肺，或从支气管肺泡灌洗液中分离肺泡巨噬细胞。进行HDAC特异性活性测定，开展蛋白质免疫印迹分析HDACs1、2、3、4和10或组蛋白赖氨酸乙酰化水平，并通过免疫荧光检查HDAC1和磷酸化HDAC1的水平及定位。与对照组相比，烧伤小鼠具有更高的HDAC特异性活性且HDAC1水平升高，但其他HDACs的水平在各组之间相当。烧伤损伤增加了细支气管和肺泡囊中HDAC1和磷酸化HDAC1的水平，并与组蛋白H3和组蛋白H4赖氨酸乙酰化的整体及特定水平降低相关。我们的分析表明，烧伤后肺部炎症可能受涉及HDACs的表观遗传机制调节，因为烧伤后HDAC活性、HDAC1表达和活性以及下游组蛋白乙酰化均发生了改变。未来的研究将探索HDAC抑制剂在逆转炎症缺陷中的作用，并最终可能为烧伤患者带来新的治疗干预措施。
