
バクテリア由来のビタミンB12がS-アデノシルメチオニン(SAM)とホスファチジルコリン(PC)合成経路を活性化し、SBP-1を介してfat-7の発現を抑制することで、C. elegansの脂質含量を低下させる。さらに、ASM-3を介したシグナル伝達がPC合成経路を増強し、脂肪滴動態の変化を引き起こすことで、食事による脂質恒常性の調節に寄与する。


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Dietary factors play a pivotal role in regulating metabolism in both health and disease. Lipid metabolism is particularly important for organismal health and longevity. However, the mechanisms by which dietary factors influence lipid metabolism remain poorly understood. Here, using the nematode C. elegans as a model system, we investigated the influence of distinct bacterial diets on fat metabolism. We found that dietary vitamin B12 activates the S-adenosyl methionine (SAM) and phosphatidylcholine (PC) biosynthetic pathways. This activation leads to elevated levels of PC, which in turn suppresses the expression of the gene fat-7 and modulates lipid droplet dynamics through the regulatory proteins SBP-1/SREBP1 and SEIP-1/SEIPIN, respectively. Additionally, we identified a feedback loop involving SBP-1-mediated regulation of acid sphingomyelinase ASM-3, which enhances the production of phospho-choline and further stimulates PC synthesis. Our localization studies further suggest that ASM-3 may act as a signaling mediator between the intestine and coelomocytes, coordinating their roles in vitamin B12-mediated fat regulation. Overall, our findings shed new light on the complex interplay between diet and metabolic regulation, with a particular emphasis on the central role of phosphatidylcholine.

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### Competing Interest Statement

The authors have declared no competing interest.

Dietary bacteria control C. elegans fat content through pathways converging at phosphatidylcholine

バクテリアによる食事がリン脂質合成経路を介してc-elegansの脂質代謝を制御する


バクテリアによる食事がリン脂質合成経路を介してC. elegansの脂質代謝を制御する
