scholarly journals Tracking biochemical changes induced by iron loading in AML12 cells with Synchrotron live cell, time-lapse infrared microscopy

2021 ◽  
Author(s):  
Clinton J Kidman ◽  
Cyril DS Mamotte ◽  
M Adrien Eynaud ◽  
Juliane Reinhardt ◽  
Jitraporn Vongsvivut ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
De Novo ◽  
Acyl Chain ◽  
Time Lapse ◽  
Biochemical Changes ◽  
Live Cell ◽  
Iron Loading ◽  
Label Free ◽  
Ftir Microscopy ◽  
Alcoholic Fatty Liver

Hepatocytes are essential for maintaining homeostasis of iron and lipid metabolism in mammals. Dysregulation of either iron or lipids has been linked with serious health consequences, including non- alcoholic fatty liver disease (NAFLD). Considered the hepatic manifestation of metabolic syndrome, NAFLD is characterised by dysregulated lipid metabolism leading to a lipid storage phenotype. Mild to moderate increases in hepatic iron have been observed in approximately 30% of individuals with NAFLD; however, direct observation of the mechanism behind this increase has remained elusive. To address this issue, we sought to determine the metabolic consequences of iron loading on cellular metabolism using live cell, time-lapse Fourier transform infrared (FTIR) microscopy utilising a synchrotron radiation source to track biochemical changes. Use of Synchrotron FTIR is non-destructive and label-free, and allowed observation of spatially-resolved, sub-cellular biochemical changes over a period of 8 hours. Using this approach, we have demonstrated that iron loading in AML12 cells induced perturbation of lipid metabolism congruent with steatosis development. Iron loaded cells had approximately three times higher relative ester carbonyl concentration compared to controls, indicating accumulation of triglycerides. The methylene/methyl ratio qualitatively suggests the acyl chain length of fatty acids in iron loaded cells increased over the 8 hour period of monitoring compared to a reduction observed in the control cells. Our findings provide direct evidence that mild to moderate iron loading in hepatocytes drives de novo lipid synthesis, consistent with a role for iron in the initial hepatic lipid accumulation that leads to development of hepatic steatosis.

scholarly journals DHT Causes Liver Steatosis via Transcriptional Regulation of SCAP in Lean female Mice

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A807-A807
Author(s):  
Stanley Andrisse ◽  
Jessie Myer ◽  
Dilip “Bobby” Bogle ◽  
Nicole Eregha ◽  
Taylor Lofton
Keyword(s):  
Lipid Metabolism ◽  
Protein Expression ◽  
Low Dose ◽  
De Novo ◽  
Polycystic Ovary ◽  
Liver Steatosis ◽  
De Novo Lipogenesis ◽  
Alcoholic Fatty Liver ◽  
Female Mice ◽  
Real Time Quantitative Pcr

Abstract Hyperandrogenemia (HA) and insulin resistance are hallmarks of polycystic ovary syndrome (PCOS). These hallmarks are also integral elements of non-alcoholic fatty liver disease (NALFD). Administering low dose dihydrotestosterone (DHT) induced a lean PCOS-like female mouse model. The molecular mechanism of HA-induced NAFLD has not been determined. We hypothesized that low dose DHT would interrupt hepatic lipid metabolism leading to NAFLD. We extracted white adipose tissue (WAT), liver, and skeletal muscle from control and low dose DHT female mice; and performed histological and biochemical lipid profiles, Western blot, immunoprecipitation, chromatin immunoprecipitation, and real-time quantitative PCR analyses. DHT lowered the 65 kD form of cytosolic SREBP1 in the liver and WAT compared to controls. However, DHT did not alter the levels of the active and inactive forms of SREBP2 in the liver and WAT. DHT increased SCAP protein expression and SCAP-SREBP1 binding via AR binding to intron-8 of SCAP leading to increased SCAP mRNA. FAS mRNA and protein expression was increased in liver of DHT mice. p-ACC levels were unaltered in liver but decreased in WAT. Other lipid metabolism pathways were examined in liver and WAT, but no changes were observed. Our findings suggest that DHT increased de novo lipogenic proteins resulting in increased NAFLD via regulation of SREBP1 in liver. We show that in the presence of DHT the SCAP-SREBP1 interaction is elevated leading to increased nuclear SREBP1 resulting in increased de novo lipogenesis. We propose that the mechanism of action is increased AR binding to an ARE in SCAP intron-8.

scholarly journals Live Cell Dynamics of Promyelocytic Leukemia Nuclear Bodies upon Entry into and Exit from Mitosis

2008 ◽  
Vol 19 (7) ◽  
pp. 3147-3162 ◽  
Author(s):  
Yi-Chun M. Chen ◽  
Constantin Kappel ◽  
Joel Beaudouin ◽  
Roland Eils ◽  
David L. Spector
Keyword(s):  
Fluorescent Protein ◽  
De Novo ◽  
Time Lapse ◽  
Cyclin B1 ◽  
Promyelocytic Leukemia ◽  
Live Cell ◽  
Nuclear Bodies ◽  
Death Domain ◽  
Directed Movement ◽  
Promyelocytic Leukemia Nuclear Bodies

Promyelocytic leukemia nuclear bodies (PML NBs) have been proposed to be involved in tumor suppression, viral defense, DNA repair, and/or transcriptional regulation. To study the dynamics of PML NBs during mitosis, we developed several U2OS cell lines stably coexpressing PML-enhanced cyan fluorescent protein with other individual marker proteins. Using three-dimensional time-lapse live cell imaging and four-dimensional particle tracking, we quantitatively demonstrated that PML NBs exhibit a high percentage of directed movement when cells progressed from prophase to prometaphase. The timing of this increased dynamic movement occurred just before or upon nuclear entry of cyclin B1, but before nuclear envelope breakdown. Our data suggest that entry into prophase leads to a loss of tethering between regions of chromatin and PML NBs, resulting in their increased dynamics. On exit from mitosis, Sp100 and Fas death domain-associated protein (Daxx) entered the daughter nuclei after a functional nuclear membrane was reformed. However, the recruitment of these proteins to PML NBs was delayed and correlated with the timing of de novo PML NB formation. Together, these results provide insight into the dynamic changes associated with PML NBs during mitosis.

scholarly journals Stable Isotope-Labeled Lipidomics to Unravel the Heterogeneous Development Lipotoxicity

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2862 ◽  
Author(s):  
Lu-Min Shih ◽  
Hsiang-Yu Tang ◽  
Ke-Shiuan Lynn ◽  
Cheng-Yu Huang ◽  
Hung-Yao Ho ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Lipid Metabolism ◽  
Stable Isotope ◽  
Fatty Liver ◽  
Lipid Droplet ◽  
De Novo ◽  
Clinical Manifestations ◽  
Lipid Profiles ◽  
Alcoholic Fatty Liver ◽  
Hepatic Lipotoxicity

Non-alcoholic fatty liver disease (NAFLD) as a global health problem has clinical manifestations ranging from simple non-alcoholic fatty liver (NAFL) to non-alcoholic steatohepatitis (NASH), cirrhosis, and cancer. The role of different types of fatty acids in driving the early progression of NAFL to NASH is not understood. Lipid overload causing lipotoxicity and inflammation has been considered as an essential pathogenic factor. To correlate the lipid profiles with cellular lipotoxicity, we utilized palmitic acid (C16:0)- and especially unprecedented palmitoleic acid (C16:1)-induced lipid overload HepG2 cell models coupled with lipidomic technology involving labeling with stable isotopes. C16:0 induced inflammation and cell death, whereas C16:1 induced significant lipid droplet accumulation. Moreover, inhibition of de novo sphingolipid synthesis by myriocin (Myr) aggravated C16:0 induced lipoapoptosis. Lipid profiles are different in C16:0 and C16:1-treated cells. Stable isotope-labeled lipidomics elucidates the roles of specific fatty acids that affect lipid metabolism and cause lipotoxicity or lipid droplet formation. It indicates that not only saturation or monounsaturation of fatty acids plays a role in hepatic lipotoxicity but also Myr inhibition exasperates lipoapoptosis through ceramide in-direct pathway. Using the techniques presented in this study, we can potentially investigate the mechanism of lipid metabolism and the heterogeneous development of NAFLD.

The correlation between lipid metabolism disorders and the prostate cancer

2020 ◽  
Vol 27 ◽  
Author(s):  
Justyna Dłubek ◽  
Jacek Rysz ◽  
Zbigniew Jabłonowski ◽  
Anna Gluba-Brzózka ◽  
Beata Franczyk
Keyword(s):  
Prostate Cancer ◽  
Fatty Acids ◽  
Lipid Metabolism ◽  
Cancer Progression ◽  
De Novo ◽  
Prostate Gland ◽  
Hdl Cholesterol ◽  
Atp Citrate Lyase ◽  
Male Population ◽  
Lipid Metabolism Disorders

: Prostate cancer is second most common cancer affecting male population all over the world. The existence of a correlation between lipid metabolism disorders and cancer of the prostate gland has been widely known for a long time. According to hypotheses, cholesterol may contribute to prostate cancer progression as a result of its participation as a signalling molecule in prostate growth and differentiation via numerous biologic mechanisms including Akt signalling and de novo steroidogenesis. The results of some studies suggest that increased cholesterol levels may be associated with higher risk of more aggressive course of disease. The aforementioned alterations in the synthesis of fatty acids are a unique feature of cancer and, therefore, it constitutes an attractive target for therapeutic intervention in the treatment of prostate cancer. Pharmacological or gene therapy aimed to reduce the activity of enzymes involved in de novo synthesis of fatty acids, FASN, ACLY (ATP citrate lyase) or SCD-1 (stearoyl-CoA desaturase) in particular, may result in cells growth arrest. Nevertheless, not all cancers are unequivocally associated with hypocholesterolaemia. It cannot be ruled out that the relationship between prostate cancer and lipid disorders is not a direct quantitative correlation between carcinogenesis and the amount of the circulating cholesterol. Perhaps the correspondence is more sophisticated and connected to the distribution of cholesterol fractions, or even sub-fractions of e.g. HDL cholesterol.

Using Deep Learning to Identify Cell and Particle in Live-Cell Time-lapse Images

2018 ◽  
Author(s):  
Hui-Jun Cheng ◽  
Chun-Yuan Lin ◽  
Cheng-Xian Wu ◽  
Che-Lun Hung ◽  
Wei-Hsiang Chen ◽  
...  
Keyword(s):  
Deep Learning ◽  
Time Lapse ◽  
Live Cell

scholarly journals How does hepatic lipid accumulation lead to lipotoxicity in non-alcoholic fatty liver disease?

2021 ◽  
Vol 15 (1) ◽  
pp. 21-35
Author(s):  
Yana Geng ◽  
Klaas Nico Faber ◽  
Vincent E. de Meijer ◽  
Hans Blokzijl ◽  
Han Moshage
Keyword(s):  
Lipid Metabolism ◽  
Liver Disease ◽  
Fatty Liver ◽  
Lipid Accumulation ◽  
Fatty Liver Disease ◽  
Lipid Uptake ◽  
Cellular Mechanisms ◽  
Alcoholic Fatty Liver ◽  
Lipid Species ◽  
Alcoholic Fatty Liver Disease

Abstract Background Non-alcoholic fatty liver disease (NAFLD), characterized as excess lipid accumulation in the liver which is not due to alcohol use, has emerged as one of the major health problems around the world. The dysregulated lipid metabolism creates a lipotoxic environment which promotes the development of NAFLD, especially the progression from simple steatosis (NAFL) to non-alcoholic steatohepatitis (NASH). Purposeand Aim This review focuses on the mechanisms of lipid accumulation in the liver, with an emphasis on the metabolic fate of free fatty acids (FFAs) in NAFLD and presents an update on the relevant cellular processes/mechanisms that are involved in lipotoxicity. The changes in the levels of various lipid species that result from the imbalance between lipolysis/lipid uptake/lipogenesis and lipid oxidation/secretion can cause organellar dysfunction, e.g. ER stress, mitochondrial dysfunction, lysosomal dysfunction, JNK activation, secretion of extracellular vesicles (EVs) and aggravate (or be exacerbated by) hypoxia which ultimately lead to cell death. The aim of this review is to provide an overview of how abnormal lipid metabolism leads to lipotoxicity and the cellular mechanisms of lipotoxicity in the context of NAFLD.

scholarly journals Lipid Metabolism Is Dysregulated before, during and after Pregnancy in a Mouse Model of Gestational Diabetes

2021 ◽  
Vol 22 (14) ◽  
pp. 7452
Author(s):  
Samuel Furse ◽  
Denise S. Fernandez-Twinn ◽  
Davide Chiarugi ◽  
Albert Koulman ◽  
Susan E. Ozanne
Keyword(s):  
Lipid Metabolism ◽  
Gestational Diabetes ◽  
Glucose Tolerance ◽  
Mouse Model ◽  
Time Course ◽  
De Novo ◽  
Lipid Analysis ◽  
Temporal Distribution ◽  
De Novo Lipogenesis ◽  
Analysis Tool

The aim of the current study was to test the hypothesis that maternal lipid metabolism was modulated during normal pregnancy and that these modulations are altered in gestational diabetes mellitus (GDM). We tested this hypothesis using an established mouse model of diet-induced obesity with pregnancy-associated loss of glucose tolerance and a novel lipid analysis tool, Lipid Traffic Analysis, that uses the temporal distribution of lipids to identify differences in the control of lipid metabolism through a time course. Our results suggest that the start of pregnancy is associated with several changes in lipid metabolism, including fewer variables associated with de novo lipogenesis and fewer PUFA-containing lipids in the circulation. Several of the changes in lipid metabolism in healthy pregnancies were less apparent or occurred later in dams who developed GDM. Some changes in maternal lipid metabolism in the obese-GDM group were so late as to only occur as the control dams’ systems began to switch back towards the non-pregnant state. These results demonstrate that lipid metabolism is modulated in healthy pregnancy and the timing of these changes is altered in GDM pregnancies. These findings raise important questions about how lipid metabolism contributes to changes in metabolism during healthy pregnancies. Furthermore, as alterations in the lipidome are present before the loss of glucose tolerance, they could contribute to the development of GDM mechanistically.

scholarly journals Lipid Acyl Chain Remodeling in Yeast

2015 ◽  
Vol 8s1 ◽  
pp. LPI.S31780 ◽  
Author(s):  
Mike F. Renne ◽  
Xue Bao ◽  
Cedric H. De Smet ◽  
Anton I. P. M. De Kroon
Keyword(s):  
Intracellular Transport ◽  
De Novo ◽  
Acyl Chain ◽  
Model Organism ◽  
Lipid Synthesis ◽  
Membrane Lipid ◽  
Lipid Homeostasis ◽  
Synthetic Process ◽  
Acyl Chains ◽  
Phospholipid Acyl Chain

Membrane lipid homeostasis is maintained by de novo synthesis, intracellular transport, remodeling, and degradation of lipid molecules. Glycerophospholipids, the most abundant structural component of eukaryotic membranes, are subject to acyl chain remodeling, which is defined as the post-synthetic process in which one or both acyl chains are exchanged. Here, we review studies addressing acyl chain remodeling of membrane glycerophospholipids in Saccharomyces cerevisiae, a model organism that has been successfully used to investigate lipid synthesis and its regulation. Experimental evidence for the occurrence of phospholipid acyl chain exchange in cardiolipin, phosphatidylcholine, phosphatidylinositol, and phosphatidylethanolamine is summarized, including methods and tools that have been used for detecting remodeling. Progress in the identification of the enzymes involved is reported, and putative functions of acyl chain remodeling in yeast are discussed.

scholarly journals Time-Lapse, Live-Cell Imaging of Potassium Efflux in Cell Exposed to Nanosecond Pulsed Electric Fields

2021 ◽  
Vol 120 (3) ◽  
pp. 223a
Author(s):  
Flavia Mazzarda ◽  
Esin B. Sozer ◽  
Julia L. Pittaluga ◽  
Claudia Muratori ◽  
P. Thomas Vernier
Keyword(s):  
Electric Fields ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Pulsed Electric Fields ◽  
Time Lapse ◽  
Live Cell ◽  
Potassium Efflux ◽  
Nanosecond Pulsed Electric Fields

scholarly journals A Narrative Review on the Role of AMPK on De Novo Lipogenesis in Non-Alcoholic Fatty Liver Disease: Evidence from Human Studies

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1822
Author(s):  
Christian von Loeffelholz ◽  
Sina M. Coldewey ◽  
Andreas L. Birkenfeld
Keyword(s):  
Liver Disease ◽  
Fatty Liver ◽  
Fatty Liver Disease ◽  
Mammalian Cells ◽  
De Novo ◽  
Adenosine Monophosphate ◽  
De Novo Lipogenesis ◽  
Alcoholic Fatty Liver ◽  
Alcoholic Fatty Liver Disease

5′AMP-activated protein kinase (AMPK) is known as metabolic sensor in mammalian cells that becomes activated by an increasing adenosine monophosphate (AMP)/adenosine triphosphate (ATP) ratio. The heterotrimeric AMPK protein comprises three subunits, each of which has multiple phosphorylation sites, playing an important role in the regulation of essential molecular pathways. By phosphorylation of downstream proteins and modulation of gene transcription AMPK functions as a master switch of energy homeostasis in tissues with high metabolic turnover, such as the liver, skeletal muscle, and adipose tissue. Regulation of AMPK under conditions of chronic caloric oversupply emerged as substantial research target to get deeper insight into the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Evidence supporting the role of AMPK in NAFLD is mainly derived from preclinical cell culture and animal studies. Dysbalanced de novo lipogenesis has been identified as one of the key processes in NAFLD pathogenesis. Thus, the scope of this review is to provide an integrative overview of evidence, in particular from clinical studies and human samples, on the role of AMPK in the regulation of primarily de novo lipogenesis in human NAFLD.

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