肝臓由来セラミドが膵臓β細胞に及ぼす影響を解明(Hepatic FoxO1 Loss Impairs Pancreatic β Cells via Liver-Derived Ceramides)

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2026-10-10 中国科学院(CAS)

中国科学院水生生物研究所の韓東教授らの研究チームは、肝臓の転写因子FoxO1の欠損が、肝臓由来の脂質を介して膵臓のインスリン分泌細胞(β細胞)を損傷する仕組みを明らかにした。FoxO1は肝臓で糖新生を促進するため、血糖値を下げる治療標的として注目されている。一方、研究チームは、マウスやゼブラフィッシュの遺伝子改変モデルなどを用いて、肝臓のFoxO1を抑制すると糖新生が減少して血糖値が低下する反面、肝臓でセラミドと呼ばれる脂質分子の産生が増え、膵臓のβ細胞の数や生存率が低下することを確認した。特に、C18・C22・C24セラミドが膵島に作用し、PP2Aの活性化を介してAKT–mTORC1シグナル経路を抑制し、β細胞のアポトーシスを引き起こすことを解明した。FoxO1は通常、セラミド合成酵素遺伝子Cers2・Cers4の発現を抑制しており、その欠損によって脂質産生の制御が失われる。本研究は、血糖降下治療において肝臓と膵臓の相互作用を考慮する重要性を示している。

肝臓由来セラミドが膵臓β細胞に及ぼす影響を解明(Hepatic FoxO1 Loss Impairs Pancreatic β Cells via Liver-Derived Ceramides)
Hepatic FoxO1 loss induces pancreatic β cell deficiency mainly via liver-derived C18/22/24 ceramides. (Image by IHB)

<関連情報>

肝臓におけるFoxO1の欠損は、肝臓由来のC18/22/24セラミドを介して膵臓β細胞機能不全を引き起こす Hepatic FoxO1 loss leads to pancreatic β cell deficiency via liver-derived C18/22/24 ceramides

Yulong Gong, Qisheng Lu, Xuehui Li, Guoli Han, Xiaochen Ma, Yulong Liu, Longwei Xi, Chaofan Wang, Gang Zhai, Zhimin Zhang, Haokun Liu, Junyan Jin, Yunxia Yang, Xiaoming Zhu, Zhan Yin, Yonghua Sun, Wenbiao Chen, Shouqi Xie, Dong Han
Cell Chemical Biology  Available online: 1 October 2026
DOI:https://doi.org/10.1016/j.chembiol.2026.09.002

Highlights

  • Hepatic FoxO1 loss induces pancreatic β cell apoptosis via inter-organ signal
  • FoxO1 acts as a transcription repressor for hepatic Cers2/4
  • Hepatic FoxO1 loss promotes C18/22/24 ceramide production via elevating Cers2/4
  • Liver-derived ceramides contribute to β cell apoptosis by inhibiting AKT-mTORC1

Significance

Organs communicate with each other through secreted signals to coordinate whole-body metabolic homeostasis. In modern lifestyles, hyperglycemia is a key feature of metabolic syndrome, and hepatic FoxO1 has emerged as a promising therapeutic target for lowering blood glucose. However, the potential side effects of inhibiting FoxO1 on other organs remain largely unknown. In this study, we discover that hepatic FoxO1 loss triggers the overproduction of specific lipid messengers—C18/22/24 ceramides—that travel to the pancreatic islets and contribute to β cell apoptosis. These findings reveal a previously unrecognized liver-β cell signaling axis and raise an important concern: therapies designed to inhibit hepatic FoxO1 may inadvertently harm pancreatic β cells, suggesting that combining FoxO1 inhibition with strategies to curb ceramide production could be necessary to preserve β cell integrity while achieving glycemic control.

Summary

Preserving pancreatic β cells is requisite for antihyperglycemic strategy. Hepatic FoxO1 represents a promising therapeutic target. However, the systemic consequences on β cell homeostasis upon hepatic FoxO1 loss and the underlying mechanism remain largely unexplored. Using liver-specific Foxo1 knockdown mouse and transgenic zebrafish models, we uncover that hepatic FoxO1 loss leads to β cell deficiency via triggering apoptosis. Lipidomic and pharmacological analyses identify that hepatic FoxO1 loss increases the liver-derived C18/22/24 ceramides, which contribute to apoptosis by inhibiting the AKT-mTORC1 pathway in β cells. The elevated C18/22/24 ceramide production is due to the upregulated transcription of hepatic ceramide synthase 2/4, while ChIP-seq and luciferase assays further decipher that FoxO1 acts as a transcriptional repressor of Cers2/4. We, therefore, report an inter-organ signal from liver-derived ceramides to pancreatic β cell homeostasis upon hepatic FoxO1 loss. These findings provide insights for therapeutic strategies aimed at preserving β cells and ameliorating hyperglycemia.

医療・健康
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