Ying-Jia Chi, Zhen-Yu Bai, Guang-Li Feng, Xiao-Hong Lai, Yu-Feng Song
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引用次数: 0
Abstract
Background: Mitochondria and endoplasmic reticulum (ER) contact sites (MERCS) constitute a functional communication platform for ER and mitochondria, and they play a crucial role in the lipid homeostasis of the liver. However, it remains unclear about the exact effects of MERCs on the neutral lipid synthesis of the liver.
Methods: In this study, the role and mechanism of MERCS in palmitic acid (PA)-induced neutral lipid imbalance in the liver was explored by constructing a lipid metabolism animal model based on yellow catfish. Given that the structural integrity of MERCS cannot be disrupted by the si-mitochondrial calcium uniporter (si-mcu), the MERCS-mediated Ca2+ signaling in isolated hepatocytes was intercepted by transfecting them with si-mcu in some in vitro experiments.
Results: The key findings were: (1) Hepatocellular MERCs sub-proteome analysis confirmed that, via activating Ip3r-Grp75-voltage-dependent anion channel (Vdac) complexes, excessive dietary PA intake enhanced hepatic MERCs. (2) Dietary PA intake caused hepatic neutral lipid deposition by MERCs recruiting Seipin, which promoted lipid droplet biogenesis. (3) Our findings provide the first proof that MERCs recruited Seipin and controlled hepatic lipid homeostasis, depending on Ip3r-Grp75-Vdac-controlled Ca2+ signaling, apart from MERCs's structural integrity. Noteworthy, our results also confirmed these mechanisms are conservative from fish to mammals.
Conclusions: The findings of this study provide a new insight into the regulatory role of MERCS-recruited SEIPIN in hepatic lipid synthesis via Ip3r-Grp75-Vdac complex-mediated Ca2+ signaling, highlighting the critical contribution of MERCS in hepatic lipid homeostasis.
期刊介绍:
Cell Communication and Signaling (CCS) is a peer-reviewed, open-access scientific journal that focuses on cellular signaling pathways in both normal and pathological conditions. It publishes original research, reviews, and commentaries, welcoming studies that utilize molecular, morphological, biochemical, structural, and cell biology approaches. CCS also encourages interdisciplinary work and innovative models, including in silico, in vitro, and in vivo approaches, to facilitate investigations of cell signaling pathways, networks, and behavior.
Starting from January 2019, CCS is proud to announce its affiliation with the International Cell Death Society. The journal now encourages submissions covering all aspects of cell death, including apoptotic and non-apoptotic mechanisms, cell death in model systems, autophagy, clearance of dying cells, and the immunological and pathological consequences of dying cells in the tissue microenvironment.