Defective Lipid Droplet–Lysosome Interaction Causes Fatty Liver Disease as Evidenced by Human Mutations in TMEM199 and CCDC115
| Autor: | David J. Rader, Joost P.H. Drenth, Adriaan G. Holleboom, Jos C. Jansen, J. Han M. Levels, Lars E. Larsen, Marjolein A.W. van den Boogert, Roos E. Eilers, Patrick L.E. Chong, Donna M. Conlon, Vinay Sachdev, Nicholas J. Hand, Wilson A. Rios-Ocampo, Eric S.G. Stroes, Miao He, Noam Zelcer, Tobias Raabe, Dirk Lefeber, Johan W. Jonker |
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| Přispěvatelé: | Experimental Vascular Medicine, ACS - Diabetes & metabolism, AGEM - Amsterdam Gastroenterology Endocrinology Metabolism, Medical Biochemistry, Vascular Medicine, ACS - Atherosclerosis & ischemic syndromes, Center for Liver, Digestive and Metabolic Diseases (CLDM) |
| Jazyk: | angličtina |
| Rok vydání: | 2022 |
| Předmět: |
Very low-density lipoprotein
Apolipoprotein B HLC hepatocyte-like cell V-ATPase assembly defects Lipophagy RC799-869 Mice FPLC fast protein liquid chromatography Lipid droplet Original Research apoB apolipoprotein B TG triglyceride biology Chemistry Fatty liver Mutations in TMEM199 and in CCDC115 Gastroenterology iPSc induced pluripotent stem cell Diseases of the digestive system. Gastroenterology Disorders of movement Donders Center for Medical Neuroscience [Radboudumc 3] medicine.anatomical_structure Hyperlipidemia Lipotoxicity qPCR quantitative polymerase chain reaction lipids (amino acids peptides and proteins) HDL-c high-density lipoprotein-cholesterol medicine.medical_specialty Nerve Tissue Proteins LDL-c low-density lipoprotein-cholesterol VLDL very low density lipoprotein Fatty liver disease Lysosome Internal medicine NAFLD medicine Animals Humans V-ATPase vacuolar-type H+-adenosine triphosphatase Hepatology OA oleic acid Membrane Proteins DMEM Dulbecco modified Eagle medium Lipid Droplets medicine.disease TC total cholesterol Fatty Liver Renal disorders Radboud Institute for Molecular Life Sciences [Radboudumc 11] Endocrinology siRNA small interfering RNA Mutation Hepatocytes biology.protein BSA bovine serum albumin NAFLD nonalcoholic fatty liver disease Steatosis Lysosomes LAL lysosomal lipase MALDI-TOF matrix-associated laser desorption/ionization time-of-flight Lipoprotein |
| Zdroj: | Cellular and molecular gastroenterology and hepatology, 13(2), 583-597. Elsevier Inc. Cellular and Molecular Gastroenterology and Hepatology Cellular and Molecular Gastroenterology and Hepatology, Vol 13, Iss 2, Pp 583-597 (2022) Cellular and Molecular Gastroenterology and Hepatology, 13, 583-597 Cellular and molecular gastroenterology and hepatology, 13(2), 583-597. HANLEY & BELFUS-ELSEVIER INC Cellular and Molecular Gastroenterology and Hepatology, 13, 2, pp. 583-597 |
| ISSN: | 2352-345X |
| Popis: | Background & Aims Recently, novel inborn errors of metabolism were identified because of mutations in V-ATPase assembly factors TMEM199 and CCDC115. Patients are characterized by generalized protein glycosylation defects, hypercholesterolemia, and fatty liver disease. Here, we set out to characterize the lipid and fatty liver phenotype in human plasma, cell models, and a mouse model. Methods and Results Patients with TMEM199 and CCDC115 mutations displayed hyperlipidemia, characterized by increased levels of lipoproteins in the very low density lipoprotein range. HepG2 hepatoma cells, in which the expression of TMEM199 and CCDC115 was silenced, and induced pluripotent stem cell (iPSC)-derived hepatocyte-like cells from patients with TMEM199 mutations showed markedly increased secretion of apolipoprotein B (apoB) compared with controls. A mouse model for TMEM199 deficiency with a CRISPR/Cas9-mediated knock-in of the human A7E mutation had marked hepatic steatosis on chow diet. Plasma N-glycans were hypogalactosylated, consistent with the patient phenotype, but no clear plasma lipid abnormalities were observed in the mouse model. In the siTMEM199 and siCCDC115 HepG2 hepatocyte models, increased numbers and size of lipid droplets were observed, including abnormally large lipid droplets, which colocalized with lysosomes. Excessive de novo lipogenesis, failing oxidative capacity, and elevated lipid uptake were not observed. Further investigation of lysosomal function revealed impaired acidification combined with impaired autophagic capacity. Conclusions Our data suggest that the hypercholesterolemia in TMEM199 and CCDC115 deficiency is due to increased secretion of apoB-containing particles. This may in turn be secondary to the hepatic steatosis observed in these patients as well as in the mouse model. Mechanistically, we observed impaired lysosomal function characterized by reduced acidification, autophagy, and increased lysosomal lipid accumulation. These findings could explain the hepatic steatosis seen in patients and highlight the importance of lipophagy in fatty liver disease. Because this pathway remains understudied and its regulation is largely untargeted, further exploration of this pathway may offer novel strategies for therapeutic interventions to reduce lipotoxicity in fatty liver disease. Graphical abstract |
| Databáze: | OpenAIRE |
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