Hepatocyte polarization is energy dependent. The establishment of polarization in collagen sandwich culture of hepatocytes requires utilization of lipid droplets and mitochondrial β-oxidation to supply ATP. Multiple cellular pathways are involved in lipid droplet homeostasis; however, mechanistic insights of how hepatocytes utilize lipid droplets during polarization remain elusive. The current study investigated the effects of various pathways involved in lipid droplet homeostasis on bioenergetics during hepatocyte polarization. The results showed that hepatocytes were dependent on lipolysis of lipid droplets to release fatty acids for β-oxidation. Inhibition of lipolysis significantly decreased cellular fatty acid and ATP levels and inhibited hepatocyte polarization, revealing that lipolysis was an important mechanism for providing energy for hepatocyte polarization. The results also demonstrated that autophagic degradation of lipid droplets (lipophagy) was not essential for breaking down lipid droplets. Conversely, autophagy contributed to lipid droplet formation and played a key role in sustaining lipid droplet stores for energy production. In addition, cholesterol biosynthesis/cholesterol esterification and de novo fatty acid synthesis also contributed to maintaining lipid droplet stores for bioenergetics during hepatocyte polarization. In summary, multiple cellular pathways are coordinated to maintain lipid droplet homeostasis and sustain fatty acid β-oxidation during hepatocyte polarization.
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http://dx.doi.org/10.1152/ajpcell.00051.2019 | DOI Listing |
Reprod Biol Endocrinol
January 2025
Department of Molecular and Developmental Medicine, Siena University, Siena, 53100, Italy.
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View Article and Find Full Text PDFJ Biol Chem
January 2025
Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany. Electronic address:
Mitochondria derive the majority of their lipids from other organelles through contact sites. These lipids, primarily phosphoglycerolipids, are the main components of mitochondrial membranes. In the cell, neutral lipids like triacylglycerides (TAGs) are stored in lipid droplets, playing an important role in maintaining cellular health.
View Article and Find Full Text PDFChem Biol Interact
January 2025
Anhui Prevention and Control Engineering Research Center for Fatty Liver Disease, Hefei, Anhui, 230032,P. R. China; The Key Laboratory of Anti-inflammatory and Immune Medicines, Ministry of Education, Hefei, China; Inflammation and Immune-Mediated Diseases Laboratory of Anhui Province, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, China. Electronic address:
Oxidative stress induced by excess ethanol is an important factor in the progression of alcoholic liver disease (ALD). In recent years, inhibiting Kelch-like ECH-associated protein 1 (KEAP1) to activate the antioxidant regulator Nuclear factor erythroid 2-related factor 2 (NRF2) has been considered an effective strategy for treating oxidative stress-related diseases, but its application in ALD remains insufficiently explored. This study aims to discover high-affinity inhibitors targeting the KEAP1 receptor.
View Article and Find Full Text PDFInt J Med Microbiol
January 2025
Division of Microbiology, Department of Infectious Medicine, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan.
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View Article and Find Full Text PDFCell Calcium
January 2025
Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
Membrane contact sites (MCS) are specialized compartments found in all eukaryotic cells that are formed between membranes of different organelles that are in close proximity. MCS have important functions as they are sites of efficient transfer of molecules between neighboring organelles. Two recent articles have used the splitFAST system to mark and follow the dynamics of membrane contact sites and used the method to highlight the importance of MCS between the endoplasmic reticulum (ER) and lipid droplets in metabolic adaptation and MCS between the ER and mitochondria in Ca signal propagation.
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