Abstract 16082: Plin2 Attenuates Cardiomyocyte Lipotoxicity

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Felix-Antoine Berube-Simard ◽  
Taha Haffar ◽  
Nicolas Bousette
Keyword(s):  
Gene Expression ◽  
Fatty Acid ◽  
Lipid Droplet ◽  
Lipid Droplets ◽  
Target Genes ◽  
Binding Protein ◽  
Neonatal Cardiomyocytes ◽  
Mediated Effects ◽  
The Subject ◽  
Rate Limiting

Diabetic cardiomyopathy is associated with excess lipid accumulation in the heart. We previously showed that oleate, a non-toxic mono-unsaturated fatty acid causes the formation of abundant lipid droplets in cardiomyocytes that were lined with Plin2, an important lipid droplet binding protein. In contrast, palmitate, a toxic saturated fatty acid, led to the formation of aberrant lipid droplets which lacked Plin2 immunoreactivity. Hypothesis: We hypothesized that Plin2 overexpression may protect against palmitate mediated lipotoxicity. Methods: We overexpressed and silenced Plin2 in rat neonatal cardiomyocytes (NCMs) by LentiVector mediated overexpression of Plin2 cDNA and shRNAs, respectively. We treated these NCMs with bovine serum albumin (51μM, vehicle control), 100-300μM oleate, or 100-300μM palmitate for 4-24 hours. We evaluated viability with the propidium iodide exclusion assay and measured gene expression by qRT-PCR. Results: Plin2 overexpression protected NCMs from the lipotoxic effects of palmitate. Conversely, silencing of Plin2 sensitized NCMs to the effects of palmitate and caused oleate, which is normally non-toxic, to induce cell death in NCMs. Interestingly, we found that Plin2 overexpression had a marked stimulatory effect on several PPAR target genes including Carnitine palmitoyl transferase 1b (Cpt1b), the rate limiting enzyme in β-oxidation. In contrast, Plin2 silencing led to a significant decrease in oleate induced expression of PPAR target genes, including Cpt1b. Conclusion: Here we showed that overexpression of Plin2, a key lipid droplet binding protein protected against lipotoxicity, while silencing it caused lipotoxicity. We show that this may be due to alterations in lipid metabolism, since Plin2 overexpression led to increased expression of key β-oxidation genes. This is important because we have previously shown that palmitate impairs β-oxidation capacity in cardiomyocytes. Therefore enhancing β-oxidation may attenuate lipotoxicity by limiting the build-up of lipid metabolites. The mechanism of Plin2 mediated effects on PPAR target gene expression, as well as the effect on lipid droplet formation are the subject of on-going studies.

ATGL-mediated triglyceride turnover and the regulation of mitochondrial capacity in skeletal muscle

2015 ◽  
Vol 308 (11) ◽  
pp. E960-E970 ◽  
Author(s):  
Ruth C. R. Meex ◽  
Andrew J. Hoy ◽  
Rachael M. Mason ◽  
Sheree D. Martin ◽  
Sean L. McGee ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid ◽  
Lipid Droplets ◽  
Target Genes ◽  
Control Point ◽  
Hormone Sensitive Lipase ◽  
Acid Oxidation ◽  
Minor Importance ◽  
Transcriptional Responses ◽  
Mitochondrial Capacity

Emerging evidence indicates that skeletal muscle lipid droplets are an important control point for intracellular lipid homeostasis and that regulating fatty acid fluxes from lipid droplets might influence mitochondrial capacity. We used pharmacological blockers of the major triglyceride lipases, adipose triglyceride lipase (ATGL) and hormone-sensitive lipase, to show that a large proportion of the fatty acids that are transported into myotubes are trafficked through the intramyocellular triglyceride pool. We next tested whether increasing lipolysis from intramyocellular lipid droplets could activate transcriptional responses to enhance mitochondrial and fatty acid oxidative capacity. ATGL was overexpressed by adenoviral and adenoassociated viral infection in C2C12 myotubes and the tibialis anterior muscle of C57Bl/6 mice, respectively. ATGL overexpression in C2C12 myotubes increased lipolysis, which was associated with increased peroxisome proliferator-activated receptor (PPAR)-∂ activity, transcriptional upregulation of some PPAR∂ target genes, and enhanced mitochondrial capacity. The transcriptional responses were specific to ATGL actions and not a generalized increase in fatty acid flux in the myotubes. Marked ATGL overexpression (20-fold) induced modest molecular changes in the skeletal muscle of mice, but these effects were not sufficient to alter fatty acid oxidation. Together, these data demonstrate the importance of lipid droplets for myocellular fatty acid trafficking and the capacity to modulate mitochondrial capacity by enhancing lipid droplet lipolysis in vitro; however, this adaptive program is of minor importance when superimposing the normal metabolic stresses encountered in free-moving animals.

scholarly journals Lipid Metabolism Gene Expression And Cellularity of Intramuscular Adipocytes Within The Longissimus Muscle of Angus- And Wagyu-Sired Cattle When Raised To A Similar Age or Body Weight

2021 ◽  
Author(s):  
Jerad Jaborek ◽  
Francis Fluharty ◽  
Kichoon Lee ◽  
Henry Zerby ◽  
Alejandro Relling
Keyword(s):  
Gene Expression ◽  
Body Weight ◽  
Fatty Acid ◽  
Lipid Metabolism ◽  
Binding Protein ◽  
Peroxisome Proliferator ◽  
Longissimus Muscle ◽  
Peroxisome Proliferator Activated Receptor ◽  
Lipid Metabolism Gene ◽  
Metabolism Gene

Abstract Background: This study investigates intramuscular (IM) adipocyte development and growth in the Longissimus muscle (LM) between Wagyu- and Angus-sired steers compared at a similar age and days on feed (DOF) endpoint or similar body weight (BW) endpoint by measuring IM adipocyte cell area and lipid metabolism gene expression. Methods: Angus-sired steers (AN, n=6) were compared with steers from two different Wagyu sires, selected for either growth or marbling, to be compared at a similar DOF (WA-GD, n=5 and WA-MD, n=5) in experiment 1 or BW (WA-GB, n=4 and WA-MB, n=5) in experiment 2, respectively. Results: In experiment 1, WA-MD steers had a greater percentage of IM fat in the LM compared with AN and WA-GD steers. In experiment 2, WA-MB steers had a greater percentage of IM fat in the LM compared with AN and WA-GB steers. The distribution of IM adipocyte area was unimodal at all biopsy collections, with IM adipocyte area becoming progressively larger as cattle age and BW increased (P≤0.01). Peroxisome proliferator activated receptor delta (PPARd) was upregulated earlier for WA-MD and WA-MB cattle compared with other steers at a similar age and BW (P≤0.02; treatment×biopsy interaction). An earlier upregulation of PPARd is believed to have then upregulated peroxisome proliferator activated receptor gamma (PPARg) at a lesser BW for WA-MB steers (P=0.09; treatment×biopsy interaction), while WA-MD steers had a greater (P≤0.04) overall mean PPARg expression compared with other steers. Glycerol-3-phosphate acyltransferase, lipin 1, and hormone sensitive lipase demonstrated expression patterns similar to PPARg and PPARd or CCAAT enhancer binding protein beta, which emphasizes their importance in marbling development and growth. Additionally, WA-MD and WA-MB steers often had a greater early expression of fatty acid transporters (fatty acid transport protein 1; P<0.02; treatment×biopsy interaction) and binding proteins (fatty acid binding protein 4) compared with other steers. With many lipolytic genes upregulated at harvest, acetyl-CoA carboxylase beta may be inhibiting fatty acid oxidation in the LM to allow greater IM fat accumulation.Conclusions: Cattle with a greater marbling propensity appear to upregulate adipogenesis at a lesser maturity through PPARd, PPARg, and possibly adipogenic regulating compounds in lysophosphatidic acid and diacylglycerol.

scholarly journals Diet-related variation in cellular retinol-binding protein type II gene expression in rat jejunum

2005 ◽  
Vol 94 (6) ◽  
pp. 890-895 ◽  
Author(s):  
Kazuhito Suruga ◽  
Masaaki Kitagawa ◽  
Hiromitsu Yasutake ◽  
Sachiko Takase ◽  
Toshinao Goda
Keyword(s):  
Gene Expression ◽  
Fatty Acid ◽  
Binding Protein ◽  
Dietary Fatty Acids ◽  
Retinol Binding Protein ◽  
Rat Jejunum ◽  
Type Ii ◽  
Feeding Period ◽  
Related Variation ◽  
Cellular Retinol Binding Protein

Cellular retinol-binding protein type II (CRBPII) is involved in the transport of vitamin A and its metabolism in the small intestine. In the present study, we demonstrated diet-related variations in CRBPII expression in rat jejunum. The CRBPII protein and mRNA levels increased in parallel after the start of feeding period regardless of whether the feeding period was restricted to the hours of darkness or of light. In addition, this variation was observed in the rats fed high-fat diet or low-fat diets, but not in those fed a fat-free diet or in fasted rats. A similar diet-induced variation was seen in the mRNA of liver-type fatty acid-binding protein in rat jejunum. In the transient transfection experiment, unsaturated fatty acid increased rat CRBPII gene promoter activity via the PPARα/retinoid X receptor-α heterodimer. Taken together, these results suggest that the diet-related variation in CRBPII expression in rat jejunum may be brought about by the transcriptional induction of CRBPII gene expression mainly triggered by dietary fatty acids.

scholarly journals Lipid-Lowering Effects of Lotus Leaf Alcoholic Extract on Serum, Hepatopancreas, and Muscle of Juvenile Grass Carp via Gene Expression

2020 ◽  
Vol 11 ◽  
Author(s):  
Junpeng Yao ◽  
Pengcheng Hu ◽  
Yanhong Zhu ◽  
Yingyan Xu ◽  
Qingsong Tan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Fatty Acid ◽  
Lipid Metabolism ◽  
Lipid Droplet ◽  
Grass Carp ◽  
Lipid Lowering ◽  
Lipid Deposition ◽  
Alcoholic Extract ◽  
Mrna Levels ◽  
Lotus Leaf

Compared with wild grass carp (Ctenopharyngodon idellus), intensively cultured fish displayed disordered lipid metabolism, showing excess lipid deposition in the hepatopancreas and muscle. Lotus leaf prevents fat accumulation in humans and may have similar effects on fish. This study explored the regulatory mechanisms by which the dietary addition of an alcoholic extract of lotus leaf (AELL) reduced lipid deposition in the hepatopancreas and muscle of juvenile grass carp. The fish (average initial weight: 34.00 ± 0.40 g) were fed four experimental diets containing different AELL levels (0, 0.07, 0.14, and 0.21%) for 8 weeks. Serum components, lipid droplet size, triacylglycerol (TAG) content, enzymatic activities, and mRNA levels of genes related to lipid metabolism in the hepatopancreas and muscle were analyzed. The results show that dietary AELL supplementation significantly reduced the TAG content and lipid droplet area in the histological sections as well as the fatty acid synthase (FAS) activity in both the hepatopancreas and muscle but enhanced the activities of lipoprotein lipase (LPL) and carnitine palmitoyltransferase I (CPT1) in both tissues. In addition, dietary AELL supplementation decreased the mRNA expression of genes involved in fatty acid uptake (cd36, fatp1/fatp4/fatp6, fabp10/fabp11, acsl1/acsl4) and de novo lipid synthesis (pgd, g6pd, and fasn) as well as the transcription factors pparg and srebf1 in the hepatopancreas and muscle but increased the mRNA levels of genes relating to lipid catabolism (cpt1a, lipe, pnpla2, lpl), lipid transportation (apob), and the transcription factor ppara in both tissues. In conclusion, dietary AELL supplementation reduced lipid accumulation in the hepatopancreas and muscle by affecting the gene expression of proteins with known effects on lipid metabolism in juvenile grass carp.

scholarly journals Bta-miR-34b regulates milk fat biosynthesis by targeting mRNA decapping enzyme 1A (DCP1A) in cultured bovine mammary epithelial cells1

2019 ◽  
Vol 97 (9) ◽  
pp. 3823-3831 ◽  
Author(s):  
Yujuan Wang ◽  
Wenli Guo ◽  
Keqiong Tang ◽  
Yaning Wang ◽  
Linsen Zan ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Lipid Droplet ◽  
Milk Fat ◽  
Fatty Acid Synthase ◽  
Binding Protein ◽  
Mammary Epithelial ◽  
Luciferase Reporter ◽  
Fatty Acid Binding ◽  
Fat Synthesis ◽  
Milk Fat Synthesis

Abstract Milk fat is a main nutritional component of milk, and it has become one of the important traits of dairy cow breeding. Recently, there is increasing evidence that microRNAs (miRNA) play significant roles in the process of milk fat synthesis in the mammary gland. Primary bovine mammary epithelial cells (BMEC) were harvested from midlactation cows and cultured in DMEM/F-12 medium with 10% fetal bovine serum, 100 units/mL penicillin, 100 µg/mL streptomycin, 5 µg/mL bovine insulin, 1 µg/mL hydrocortisone, and 2 µg/mL bovine prolactin. We found that miR-34b mimic transfection in BMEC reduced the content of intracellular triacylglycerol (TAG) and lipid droplet accumulation via triacylglycerol assay and Oil Red O staining; meanwhile, overexpression of miR-34b inhibited mRNA expression of lipid metabolism-related genes such as peroxisome proliferator-activated receptor gamma (PPARγ), fatty acid synthase (FASN), fatty acid binding protein 4 (FABP4), and CCAAT enhancer binding protein alpha (C/EBPα). Whereas miR-34b inhibitor resulted in completely opposite results. Furthermore, q-PCR and western blot analysis revealed the mRNA and protein expression levels of DCP1A were downregulated in miR-34b mimic transfection group and upregulated in miR-34b inhibitor group. Moreover, luciferase reporter assays verified that DCP1A was the direct target of miR-34b and DCP1A gene silencing in BMEC-inhibited TAG accumulation and suppressed lipid droplet formation. In conclusion, these findings revealed a novel miR-34b–DCP1A axis that has a significant role in regulating milk fat synthesis and suggested that miR-34b may be used to improve the beneficial ingredients in milk.

Gene Expression of Heart- and Adipocyte-Fatty Acid-Binding Protein and Correlation With Intramuscular Fat in Chinese Chickens

2008 ◽  
Vol 19 (3) ◽  
pp. 190-194 ◽  
Author(s):  
W. J. Li ◽  
H. B. Li ◽  
J. L. Chen ◽  
G. P. Zhao ◽  
M. Q. Zheng ◽  
...  
Keyword(s):  
Gene Expression ◽  
Fatty Acid ◽  
Fatty Acid Binding Protein ◽  
Binding Protein ◽  
Intramuscular Fat ◽  
Fatty Acid Binding ◽  
Acid Binding Protein

scholarly journals Carbohydrate Response Element Binding Protein Gene Expression Is Positively Regulated by Thyroid Hormone

Endocrinology ◽  
2009 ◽  
Vol 150 (7) ◽  
pp. 3417-3424 ◽  
Author(s):  
Koshi Hashimoto ◽  
Emi Ishida ◽  
Shunichi Matsumoto ◽  
Shuichi Okada ◽  
Masanobu Yamada ◽  
...  
Keyword(s):  
Gene Expression ◽  
Thyroid Hormone ◽  
Target Genes ◽  
Binding Protein ◽  
Gene Promoter ◽  
Direct Repeat ◽  
Transcriptional Level ◽  
Hepatic Lipogenesis ◽  
Response Element ◽  
Element Binding Protein

The molecular mechanism of thyroid hormone (TH) effects to fatty acid metabolism in liver is yet to be clear. The carbohydrate response element-binding protein (ChREBP) as well as sterol response element-binding protein (SREBP)-1c plays a pivotal role in hepatic lipogenesis. Both SREBP-1c and ChREBP are target genes of liver X receptors (LXRs). Because LXRs and TH receptors (TRs) cross talk mutually in many aspects of transcription, we examined whether TRs regulate the mouse ChREBP gene expression. In the current study, we demonstrated that TH up-regulated mouse ChREBP mRNA and protein expression in liver. Run-on and luciferase assays showed that TH and TR-β1 positively regulated the ChREBP gene transcription. The mouse ChREBP gene promoter contains two direct repeat-4 sites (LXRE1 and LXRE2) and EMSAs demonstrated that LXR-α and TR-β1 prefer to bind LXRE1 and LXRE2, respectively. The direct repeat-4 deletion and LXRE2 mutants of the promoter deteriorate the positive regulation by TR-β1, indicating that LXRE2 is functionally important for the regulation. We also showed that human ChREBP gene expression and promoter activities were up-regulated by TH. These data suggest that ChREBP mRNA expression is positively regulated by TR-β1 and TH at the transcriptional level in mammals. This novel observation indicates that TH fine-tunes hepatic lipogenesis via regulating SREBP-1c and ChREBP gene expression reciprocally.

Analyses of the Inducible Cyclic Adenosine 3′,5′-Monophosphate Early Repressor (ICER) and cAMP Response Element Binding Protein (CREB) in HL60 Cells: New Insight Leukemogenesis?.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2251-2251
Author(s):  
Martina Pigazzi ◽  
Elena Manara ◽  
Marta Campo DellOrto ◽  
Emanuela Ricotti ◽  
Giuseppe Basso
Keyword(s):  
Gene Expression ◽  
Target Genes ◽  
Luciferase Activity ◽  
Binding Protein ◽  
Expression System ◽  
Consensus Sequence ◽  
Response Element ◽  
Hl60 Cells ◽  
Element Binding Protein ◽  
Exogenous Expression

Abstract The cyclic AMP response-element binding protein (CREB) is a transcription factor that controls genes that regulate cell differentiation, proliferation and survival. CREB protein overexpression has previously been demonstrated in lymphoid and myeloid leukemia. In contrast, it is lower in healthy samples. To understand CREB role in hematopoiesis and leukemogenesis we focused on ICER (Inducible Cyclic Adenosine 3′,5′-monophosphate early repressor). We hypothesize that ICER, CREB endogenous antagonist, deserves a special consideration in CREB function and in the activation of gene expression. ICER directs its specific binding to cAMP response elements (CREs) functioning as a potent repressor of CREB binding and therefore of cAMP-induced transcription. It has been already demonstrated that ICER directly participates in cell fate in other systems. We have previously found that ICER mRNA was at low level at diagnosis of leukemia, whereas it increased in documented remission samples collected during follow up. We constructed an expression vector for ICER and induced its exogenous expression in HL60 cells. We then tested transcription and translation of a series of genes known to have a direct link with the members of the cAMP/CREB pathway by quantitative gene expression analysis and western blot. To determine wheter ICER protein affected identical cellular targets of CREB by repressing CRE containing promoters, we examined luciferase activity when directed by a promoter made up of 4XCREs sequences post ICER transient induction. By chromatin immunoprecipitation assay (ChIP) we looked at specific genes promoters binding, also in permanent ectopic ICER expression system. Results revealed that ICER protein was detected after 24 hours post transfection with sustained induction after 48 hours, whereas CREB mRNA and protein are down regulated. Density Array made up of 96 genes cited in CREB database (http://natural.salk.edu/CREB) for the high predictive value to contain CRE consensus sequence in their promoter revealed a wide genes expression alterations occurring over time post ICER exogenous expression, counteracting CREB transcriptional function. For some genes we confirmed that mRNA down regulation was representative of protein downregulation. We revealed that luciferase activity was strongly reduced by ICER transient induction. Moreover ChIP analyses revealed that CREB binds to the Bcl-2, ICER and CyA1 promoters in HL60 controlling their transcription. This binding was strongly reduced, in particular for Bcl-2, after ICER stable transfection in HL60 confirming its important role in gene expression reduction. Finally, we hypothesize that CREB over expression might up-regulate target genes, affecting cell proliferation and survival at diagnosis of leukaemia. Insufficient ICER expression might fail to counteract these events. These findings represent an important first step in the understanding of the physiological processes linked to the cAMP/CREB/ICER pathway. The future understanding of ICER role in blocking cAMP activation pathway and the finding of a pool of CREB target genes in HL60 may help understanding leukemogenesis.

scholarly journals Human Sterol Regulatory Element-Binding Protein 1a Contributes Significantly to Hepatic Lipogenic Gene Expression

2015 ◽  
Vol 35 (2) ◽  
pp. 803-815 ◽  
Author(s):  
Andreas Bitter ◽  
Andreas K. Nüssler ◽  
Wolfgang E. Thasler ◽  
Kathrin Klein ◽  
Ulrich M. Zanger ◽  
...  
Keyword(s):  
Gene Expression ◽  
Human Liver ◽  
Target Genes ◽  
Binding Protein ◽  
Regulatory Element ◽  
Lipogenic Gene ◽  
Knock Down ◽  
Lipogenic Gene Expression ◽  
Element Binding Protein ◽  
Sterol Regulatory Element

Background/Aims: Sterol regulatory element-binding protein (SREBP) 1, the master regulator of lipogenesis, was shown to be associated with non-alcoholic fatty liver disease, which is attributed to its major isoform SREBP1c. Based on studies in mice, the minor isoform SREBP1a is regarded as negligible for hepatic lipogenesis. This study aims to elucidate the expression and functional role of SREBP1a in human liver. Methods: mRNA expression of both isoforms was quantified in cohorts of human livers and primary human hepatocytes. Hepatocytes were treated with PF-429242 to inhibit the proteolytic activation of SREBP precursor protein. SREBP1a-specifc and pan-SREBP1 knock-down were performed by transfection of respective siRNAs. Lipogenic SREBP-target gene expression was analyzed by real-time RT-PCR. Results: In human liver, SREBP1a accounts for up to half of the total SREBP1 pool. Treatment with PF-429242 indicated SREBP-dependent auto-regulation of SREBP1a, which however was much weaker than of SREBP1c. SREBP1a-specifc knock-down also reduced significantly the expression of SREBP1c and of SREBP-target genes. Regarding most SREBP-target genes, simultaneous knock-down of both isoforms resulted in effects of only similar extent as SREBP1a-specific knock-down. Conclusion: We here showed that SREBP1a is significantly contributing to the human hepatic SREBP1 pool and has a share in human hepatic lipogenic gene expression.

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