飲食調節線蟲脂肪之移動及其與相關胞器的關係

Abstract

飲食對於維持生物體脂肪恆定的影響甚鉅，因為食物不僅提供能量，其中所含的營養物質亦能調控脂肪之代謝過程。生物體分解脂肪能力下降造成了肥胖，進而引發糖尿病、心血管疾病及相關癌症的發生。雖然已知許多胞器如油滴、過氧化物酶體、溶酶體與粒線體能參與脂肪的降解，但是食物如何調控這些胞器去啟動分解脂肪的機制目前並不清楚。我們先前的實驗表明，將線蟲餵食在不同細菌食物下，線蟲體內脂肪含量並不相同。藉由光學顯微鏡觀察染色之胞器和具有特定胞器的螢光標記之線蟲，並輔以電子顯微鏡合併觀察，結果顯示攝取不同的細菌食物會對特定胞器之數量及型態產生影響。另外，我們亦發現部分酵素會在該特定胞器中影響與飲食相關的脂肪堆積。概括上述結果，本研究顯示飲食可主導特定胞器以調節宿主的脂肪代謝。

Diets have a great impact on lipid homeostasis of an organism. In addition to providing energy, nutrients of diets regulate lipid metabolism. Imbalance in lipid homeostasis has been associated with obesity, resulting in many health issues, including diabetes, heart diseases, and certain cancers. While several organelles such as lipid droplet, peroxisome, lysosome and mitochondria, participate in lipid breakdown, how diets modulate lipid degradation in relation to these organelles remains to be elucidated. We fed C. elegans different bacterial diets and found C. elegans had different levels of fat in the intestine. Using vital dyes and specific organelle markers in combination with light and electron microscopy, we showed that bacterial diets affect specific organelle numbers and morphology. In addition, we identified a few enzymes localized to the specific organelles in diet-dependent fat storage. Altogether, our results present a model that diets affect fat metabolism through specific enzymes in specific organelles.