scholarly journals Lipid droplet screen in human hepatocytes identifies TRRAP as a regulator of cellular triglyceride metabolism

2021 ◽  
Author(s):  
Deepti Abbey ◽  
Donna Conlon ◽  
Christopher Rainville ◽  
Susannah Elwyn ◽  
Katherine Quiroz‐Figueroa ◽  
...  
Keyword(s):  
Lipid Droplet ◽  
Human Hepatocytes ◽  
Triglyceride Metabolism

scholarly journals CRISPR-Cas9-mediated knockout of SPRY2 in human hepatocytes leads to increased glucose uptake and lipid droplet accumulation

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Naomi L. Cook ◽  
Milos Pjanic ◽  
Andrew G. Emmerich ◽  
Abhiram S. Rao ◽  
Susanne Hetty ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Protein Kinases ◽  
Lipid Droplet ◽  
Hepg2 Cells ◽  
Metabolic Diseases ◽  
Association Studies ◽  
Cholesterol Biosynthesis ◽  
Human Hepatocytes ◽  
Signalling Pathways ◽  
Genome Wide Association Studies

Abstract Background The prevalence of obesity and its comorbidities, including type 2 diabetes mellitus (T2DM), is dramatically increasing throughout the world; however, the underlying aetiology is incompletely understood. Genome-wide association studies (GWAS) have identified hundreds of genec susceptibility loci for obesity and T2DM, although the causal genes and mechanisms are largely unknown. SPRY2 is a candidate gene identified in GWAS of body fat percentage and T2DM, and has recently been linked to insulin production in pancreatic β-cells. In the present study, we aimed to further understand SPRY2 via functional characterisation in HepG2 cells, an in vitro model of human hepatocytes widely used to investigate T2DM and insulin resistance. Methods CRISPR-Cas9 genome editing was used to target SPRY2 in HepG2 cells, and the functional consequences of SPRY2 knockout (KO) and overexpression subsequently assessed using glucose uptake and lipid droplet assays, measurement of protein kinase phosphorylation and RNA sequencing. Results The major functional consequence of SPRY2 KO was a significant increase in glucose uptake, along with elevated lipid droplet accumulation. These changes were attenuated, but not reversed, in cells overexpressing SPRY2. Phosphorylation of protein kinases across key signalling pathways (including Akt and mitogen activated protein kinases) was not altered after SPRY2 KO. Transcriptome profiling in SPRY2 KO and mock (control) cells revealed a number of differentially expressed genes related to cholesterol biosynthesis, cell cycle regulation and cellular signalling pathways. Phospholipase A2 group IIA (PLA2G2A) mRNA level was subsequently validated as significantly upregulated following SPRY2 KO, highlighting this as a potential mediator downstream of SPRY2. Conclusion These findings suggest a role for SPRY2 in glucose and lipid metabolism in hepatocytes and contribute to clarifying the function of this gene in the context of metabolic diseases.

scholarly journals PNPLA2 influences secretion of triglyceride-rich lipoproteins by human hepatoma cells

2019 ◽  
Vol 60 (6) ◽  
pp. 1069-1077 ◽  
Author(s):  
Apostolos Taxiarchis ◽  
Hovsep Mahdessian ◽  
Angela Silveira ◽  
Rachel M. Fisher ◽  
Ferdinand M. van’t Hooft
Keyword(s):  
Lipid Droplet ◽  
Physiological Role ◽  
Hepatoma Cells ◽  
Human Hepatoma ◽  
Human Hepatoma Cells ◽  
Triglyceride Metabolism ◽  
Triglyceride Hydrolysis ◽  
Triglyceride Accumulation ◽  
Huh7 Cells ◽  
Microscopy Analysis

Patatin-like phospholipase domain-containing proteins (PNPLAs) are involved in triglyceride hydrolysis and lipid-droplet homeostasis in mice, but the physiological significance of the PNPLAs for triglyceride metabolism in human hepatocytes is unclear. Here, we investigate the roles of PNPLA2, PNPLA3, and PNPLA4 in triglyceride metabolism of human Huh7 and HepG2 hepatoma cells using gene-specific inhibition methods. siRNA inhibition of PNPLA3 or PNPLA4 is not associated with changes in triglyceride hydrolysis, secretion of triglyceride-rich lipoproteins (TRLs), or triglyceride accumulation. However, PNPLA2 siRNA inhibition, both in the absence and presence of oleate-containing medium, or treatment with the PNPLA2 inhibitor Atglistatin reduced intracellular triglyceride hydrolysis and decreased TRL secretion. In contrast, PNPLA2 inhibition showed no effects on lipid-droplet homeostasis, which is the primary physiological function of PNPLA2 in nonhepatic tissues. Moreover, confocal microscopy analysis found no clear evidence for the localization of PNPLA2 around lipid droplets. However, significant colocalization of PNPLA2 with the endoplasmic reticulum marker protein disulfide-isomerase was found in HepG2 and Huh7 cells with Rcoloc values of 0.61 ± 0.06 and 0.81 ± 0.05, respectively. In conclusion, PNPLA2 influences TRL secretion, but is not involved in lipid-droplet homeostasis in human hepatoma cells, a physiological role that is quite distinct from the metabolic function of PNPLA2 in nonhepatic tissues.

Regulation of Triglyceride Metabolism. III. Emerging role of lipid droplet protein ADFP in health and disease

2007 ◽  
Vol 292 (6) ◽  
pp. G1465-G1468 ◽  
Author(s):  
Benny Hung-Junn Chang ◽  
Lawrence Chan
Keyword(s):  
Potential Function ◽  
Lipid Droplet ◽  
Triglyceride Metabolism ◽  
Health And Disease ◽  
Space Limitation ◽  
Lipid Droplet Protein

ADFP is the major lipid droplet protein present in all cells that accumulate lipids either normally or abnormally. Although discovered about 15 years ago, it was only in the last few years that we began to have a working knowledge of its possible role in lipid droplet homeostasis at the whole organism level. In this perspective, we concentrate on the potential function of ADFP in various tissues. Space limitation has precluded a complete cataloging of all publications on the topic. We instead highlight some of the salient developments in the last few years.

PNPLA3 variant M148 causes resistance to starvation‐mediated lipid droplet autophagy in human hepatocytes

2018 ◽  
Vol 120 (1) ◽  
pp. 343-356 ◽  
Author(s):  
Florentina Negoita ◽  
Julia Blomdahl ◽  
Sebastian Wasserstrom ◽  
Martin E. Winberg ◽  
Peter Osmark ◽  
...  
Keyword(s):  
Lipid Droplet ◽  
Human Hepatocytes

scholarly journals Conserved valproic-acid-induced lipid droplet formation in Dictyostelium and human hepatocytes identifies structurally active compounds

2011 ◽  
Vol 5 (2) ◽  
pp. 231-240 ◽  
Author(s):  
L. M. Elphick ◽  
N. Pawolleck ◽  
I. A. Guschina ◽  
L. Chaieb ◽  
D. Eikel ◽  
...  
Keyword(s):  
Valproic Acid ◽  
Lipid Droplet ◽  
Droplet Formation ◽  
Human Hepatocytes ◽  
Active Compounds ◽  
Lipid Droplet Formation

Evaluation of Flutamide Genotoxicity in Rats and in Primary Human Hepatocytes

2000 ◽  
Vol 86 (3) ◽  
pp. 129-134 ◽  
Author(s):  
Antonietta MartelliNote ◽  
Giulia Brambilla Campart ◽  
Roberto Carrozzino ◽  
Marco Ghia ◽  
Francesca Mattioli ◽  
...  
Keyword(s):  
Human Hepatocytes ◽  
Primary Human Hepatocytes

Towards unravelling the role of the lipid droplet-associated proteins perilipin, adipophilin, and TIP47 in hepatocellular carcinoma

2009 ◽  
Vol 47 (01) ◽  
Author(s):  
BK Straub ◽  
S Singer ◽  
J Lehmann-Koch ◽  
H Heid ◽  
E Specht ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Lipid Droplet ◽  
Associated Proteins

Chronic HBV infection impairs induction of interferon responsive genes in human hepatocytes repopulating the liver of uPA/SCID mice

2010 ◽  
Vol 48 (01) ◽  
Author(s):  
M Lütgehetmann ◽  
T Volz ◽  
AW Lohse ◽  
JH Bockmann ◽  
J Petersen ◽  
...  
Keyword(s):  
Human Hepatocytes ◽  
Scid Mice ◽  
Hbv Infection ◽  
Chronic Hbv Infection ◽  
Chronic Hbv

Characterization of the lipid droplet-associated protein MLDP in human tissues and in hepatocyte steatosis

2010 ◽  
Vol 48 (01) ◽  
Author(s):  
M Hashani ◽  
M koenig ◽  
LM Pawella ◽  
P Schirmacher ◽  
BK Straub
Keyword(s):  
Lipid Droplet ◽  
Human Tissues ◽  
Hepatocyte Steatosis
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