Warburg效应在瘢痕疙瘩形成中的作用和分子调控机制研究

Keloid is a clinical challenge and its exact pathogenesis still remains to be clarified. Keloid is also regarded as tumor because of its invading growth. Warburg effect, as an unique style of energy metabolism for tumors, plays an important role in tumor growth and metastasis. Polypyrimidine tract-binding protein (PTB) is one of the major regulatory molecules of Warburg effect in tumors. Though influencing the alternative splicing of PKM, PTB could enhance the expression of pyruvate kinase M2 isoform (PKM2), which would activate Warburg effect. In our preliminary research, the expression of PTB in keloid was observed to increase significantly than normal skin, and it shifted the alternative splicing of PKM from PKM1 to PKM2. The above results suggest that fibroblasts from keloid may produce their energy through Warburg effect. However, it is unclear that if Warburg effect is specific for keloid, or a stress response during scar development. And, the role and molecular mechanism of Warburg effect in keloid development remains poorly understood. In this project, we will carry out work from the three aspects: (1). The Warburg effect in various types of scars and normal skin. (2). The role of Warburg effect in extracellular matrix, proliferation, apoptosis and autophage in keloid fibroblasts. (3). The molecular mechanism of PTB in regulating Warburg effect. The project would provide new insights into keloid pathogenesis researches, and contribute to keloid screening, prevention, drug discovery and clinical therapy.

瘢痕疙瘩是临床治疗难题，其发病机制尚不清楚，由于浸润生长的特性，也被看做皮肤肿瘤。Warburg效应是肿瘤独特的能量代谢方式，对肿瘤生长转移起重要作用。在肿瘤细胞PTB是Warburg效应主要调控分子，其通过改变PKM选择性剪接启动Warburg效应。我们前期研究发现PTB在瘢痕疙瘩中表达升高，且可以调控PKM选择性剪接，这提示瘢痕疙瘩中也可能存在Warburg效应。但Warburg效应是瘢痕疙瘩特有的能量代谢方式还是瘢痕形成中的应激反应、以及其在瘢痕疙瘩形成中的作用和分子调控机制尚不清楚。为此本项目拟对不同类型瘢痕中Warburg效应发生情况，Warburg效应对成纤维细胞细胞外基质分泌、增殖、凋亡和自噬等作用，瘢痕疙瘩中PTB调控Warburg效应的分子机制三个方面展开研究。本项目成功实施可以为瘢痕疙瘩发病机制研究开辟新道路，为瘢痕疙瘩筛查、预防、治疗和药物研发提供新科学线索。

瘢痕疙瘩是临床治疗难题，其发病机制尚不清楚，由于浸润生长的特性，也被看做皮肤肿.瘤。Warburg效应是肿瘤独特的能量代谢方式，对肿瘤生长转移起重要作用。在肿瘤细胞PTB是Warburg效应主要调控分子，其通过改变PKM选择性剪接启动Warburg效应。我们前期研究发现PTB在瘢痕疙瘩中表达升高，且可以调控PKM选择性剪接，这提示瘢痕疙瘩中也可能存在Warburg效应。但Warburg效应是瘢痕疙瘩特有的能量代谢方式还是瘢痕形成中的应激反应、以及其在瘢痕疙瘩形成中的作用和分子调控机制尚不清楚。为此本项目拟对不同类型瘢痕中Warburg效应发生情况，Warburg效应对成纤维细胞细胞外基质分泌、增殖、凋亡和自噬等作用，瘢痕疙瘩中PTB调控Warburg效应的分子机制三个方面展开研究。1.我们在体外培养了各种类型瘢痕和正常皮肤的成纤维细胞，检测发现瘢痕疙瘩成纤维细胞产生更多乳酸，摄取更多葡萄糖，并且糖酵解关键酶表达增高，而其他类型瘢痕不存在类似现象，这说明瘢痕疙瘩内存在warburg效应。2.用乳酸脱氢酶的抑制剂草氨酸钠抑制瘢痕疙瘩中的Warburg效应可引起细胞迁移力降低、胶原分泌减少、细胞凋亡增多及细胞增殖活性的降低，进一步研究发现细胞增殖活性降低是通过Akt-GSK3β-Cyclin D1信号通路诱导细胞发生G0/G1周期阻滞而引起的。3.敲减或者过表达瘢痕疙瘩成纤维细胞的PTB，可以抑制或者阻断瘢痕疙瘩成纤维细胞的warburg效应，与此同时促使瘢痕疙瘩成纤维细胞PKM的选择性剪接发生改变，PTB敲减时 PKM1表达上调PKM2表达下调，PTB过表达时 PKM1表达下调PKM2表达上调。以上研究结果说明warburg效应是瘢痕疙瘩不同于其它类型瘢痕的特有的能量代谢方式，warburg效应可以通过影响瘢痕疙瘩成纤维细胞增殖、凋亡、迁移等生物学行为影响瘢痕疙瘩形成，PTB可以通过改变PKM的选择性剪切调控瘢痕疙瘩中的warburg效应。