瓜蒌薤白提取物通过活化棕色脂肪抑制动脉粥样斑块形成的机制研究

Brown adipose tissue (BAT) activation decreases plasma glucose, triglyceride and cholesterol levels and protects from atherosclerosis development, which imitates the effect of the traditional Chinese herbal medicine, trichosanthes kirilowii and allium macrostemon decoction. Thus, we hypothesize that BAT might be activated by trichosanthes kirilowii and allium macrostemon extract (TKAM). Our investigation showed that the BAT was activated and the atherosclerosis development was attenuated in high-fat fed mice exposed to TKAM. And significant changes of expression levels of Sam68 and miR-381 were also observed. To further investigate the mechanism of TKAM, we proceed to a mouse model of brown adipose tissue defect (UCP-1-/-) to corroborate that the effects of TKAM are in dependence on BAT activation. Regulations of the expression levels achieved by adenovirus transgenic vectors are conducted in both high-fat fed mice and progenitor adipocytes to investigate the role of Sam68 and miR-381 in BAT activation due to TKAM. Finally, we apply the synthesis of specific nucleotide sequence in combination with point mutation and gene co-transfection via adenovirus vectors to investigate the interactions between miR-381 and Sam68 and to identify the target BAT transcription factors of Sam68. Data from our study will not only demonstrate the mechanism of TKAM’s protection from atherosclerosis, but also provide new methods and targets for relative clinical application.

活化棕色脂肪组织（BAT）可以降低血糖、血脂并可抑制动脉粥样硬化斑块的形成，与中药方剂“瓜蒌薤白汤”的功效较为相似。因此我们设想瓜蒌薤白提取物（TKAM）是否可能通过活化BAT发挥其治疗作用。前期研究发现：TKAM可活化高脂喂养小鼠体内BAT并抑制动脉粥样斑块的进展，其中Sam68及miR-381前后水平存在显著性差异。为进一步探究TKAM作用机制，我们首先通过构建BAT基因敲除小鼠模型，验证TKAM是否依赖于活化BAT发挥其功效。随后在高脂喂养小鼠模型及脂肪前体细胞中通过转基因手段观察Sam68及miR-381水平变化对于TKAM活化BAT的影响。最后联合应用基因点突变，体外核苷酸序列合成以及基因共转染等多种分子生物学方法，明确Sam68及miR-381的作用靶点。该项目的研究不但有助于揭示TKAM抑制粥样斑块形成的具体机制，而且还可能为今后通过中西医结合手段干预治疗提供新方法和新靶点。