scholarly journals Maternal DHA supplementation influences sex-specific disruption of placental gene expression following early prenatal stress

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Eldin Jašarević ◽  
Patrick M. Hecht ◽  
Kevin L. Fritsche ◽  
David C. Geary ◽  
Rocío M. Rivera ◽  
...  
Keyword(s):  
Prenatal Stress ◽  
Disease Risk ◽  
Control Diet ◽  
Hypoxia Inducible Factor ◽  
Peroxisome Proliferator ◽  
Omega 3 ◽  
Early Life Adversity ◽  
Peroxisome Proliferator Activated Receptor ◽  
Underlying Mechanisms ◽  
Dha Enrichment

AbstractEarly life adversity is widely recognized as a key risk factor for early developmental perturbations and contributes to the presentation of neuropsychiatric disorders in adulthood. Neurodevelopmental disorders exhibit a strong sex bias in susceptibility, presentation, onset, and severity, although the underlying mechanisms conferring vulnerability are not well understood. Environmental perturbations during pregnancy, such as malnutrition or stress, have been associated with sex-specific reprogramming that contribute to increased disease risk in adulthood, whereby stress and nutritional insufficiency may be additive and further exacerbate poor offspring outcomes. To determine whether maternal supplementation of docosahexanoic acid (DHA) exerts an effect on offspring outcome following exposure to early prenatal stress (EPS), dams were fed a purified 10:1 omega-6/omega-3 diet supplemented with either 1.0% preformed DHA/kg feed weight (DHA-enriched) or no additional DHA (denoted as the control diet, CTL). Dams were administered chronic variable stress during the first week of pregnancy (embryonic day, E0.5–7.5), and developmental milestones were assessed at E 12.5. Exposure to early prenatal stress (EPS) decreased placenta and embryo weight in males, but not females, exposed to the CTL diet. DHA enrichment reversed the sex-specific decrease in placenta and embryo weight following EPS. Early prenatal exposure upregulated expression of genes associated with oxygen and nutrient transport, including hypoxia inducible factor 3α (HIF3α), peroxisome proliferator-activated receptor alpha (PPARα), and insulin-like growth binding factor 1 (IGFBP1), in the placenta of CTL diet males exposed to EPS. DHA enrichment in EPS-exposed animals abrogated the male-specific upregulation of PPARα, HIF3α, and IGFBP1. Taken together, these studies suggest that maternal dietary DHA enrichment may buffer against maternal stress programming of sex-specific outcomes during early development.

scholarly journals Maternal DHA supplementation influences sex-specific disruption of placental gene expression following early prenatal stress

2020 ◽  
Author(s):  
Eldin Jašarević ◽  
Patrick M. Hecht ◽  
Kevin L. Fritsche ◽  
David C. Geary ◽  
Rocío M. Rivera ◽  
...  
Keyword(s):  
Prenatal Stress ◽  
Disease Risk ◽  
Control Diet ◽  
Hypoxia Inducible Factor ◽  
Peroxisome Proliferator ◽  
Omega 3 ◽  
Early Life Adversity ◽  
Peroxisome Proliferator Activated Receptor ◽  
Underlying Mechanisms ◽  
Dha Enrichment

Abstract Early life adversity is widely recognized as a key risk factor for early developmental perturbations and contributes to the presentation of neuropsychiatric disorders in adulthood. Neurodevelopmental disorders exhibit a strong sex-bias in susceptibility, presentation, onset and severity, although the underlying mechanisms conferring vulnerability are not well understood. Environmental perturbations during pregnancy, such as malnutrition or stress, have been associated with sex-specific reprogramming that contribute to increased disease risk in adulthood, whereby stress and nutritional insufficiency may be additive and further exacerbate poor offspring outcomes. To determine whether maternal supplementation of docosahexanoic acid (DHA) exerts an effect on offspring outcome following exposure to early prenatal stress (EPS), dams were fed a purified 10:1 omega-6/omega-3 diet supplemented with either 1.0% preformed DHA/kg feed weight (DHA-enriched) or no additional DHA (denoted as the control diet, CTL). Dams were administered chronic variable stress during the first week of pregnancy (Embryonic day, E0.5 – 7.5) and developmental milestones were assessed at E 12.5. Exposure to early prenatal stress (EPS) decreased placenta and embryo weight in males, but not females, exposed to the CTL diet. DHA-enrichment reversed the sex-specific decrease in placenta and embryo weight following EPS. Early prenatal exposure upregulated expression of genes associated with oxygen and nutrient transport, including hypoxia inducible factor 3α (HIF3α), peroxisome proliferator-activated receptor alpha (PPARα), and insulin like growth binding factor 1 (IGFBP1), in placenta of CTL diet males exposed to EPS. DHA-enrichment in EPS-exposed animals abrogated the male-specific upregulation of PPARα, HIF3α, and IGFBP1. Taken together, these studies suggest that maternal dietary DHA enrichment may buffer against maternal stress programming of sex-specific outcomes during early development.

scholarly journals Maternal DHA supplementation influences sex-specific disruption of placental gene expression following early prenatal stress

2021 ◽  
Author(s):  
Eldin Jašarević ◽  
Patrick M. Hecht ◽  
Kevin L. Fritsche ◽  
David C. Geary ◽  
Rocío M. Rivera ◽  
...  
Keyword(s):  
Prenatal Stress ◽  
Disease Risk ◽  
Control Diet ◽  
Hypoxia Inducible Factor ◽  
Peroxisome Proliferator ◽  
Omega 3 ◽  
Early Life Adversity ◽  
Peroxisome Proliferator Activated Receptor ◽  
Underlying Mechanisms ◽  
Dha Enrichment

Abstract Early life adversity is widely recognized as a key risk factor for early developmental perturbations and contributes to the presentation of neuropsychiatric disorders in adulthood. Neurodevelopmental disorders exhibit a strong sex-bias in susceptibility, presentation, onset and severity, although the underlying mechanisms conferring vulnerability are not well understood. Environmental perturbations during pregnancy, such as malnutrition or stress, have been associated with sex-specific reprogramming that contribute to increased disease risk in adulthood, whereby stress and nutritional insufficiency may be additive and further exacerbate poor offspring outcomes. To determine whether maternal supplementation of docosahexanoic acid (DHA) exerts an effect on offspring outcome following exposure to early prenatal stress (EPS), dams were fed a purified 10:1 omega-6/omega-3 diet supplemented with either 1.0% preformed DHA/kg feed weight (DHA-enriched) or no additional DHA (denoted as the control diet, CTL). Dams were administered chronic variable stress during the first week of pregnancy (Embryonic day, E0.5 – 7.5) and developmental milestones were assessed at E 12.5. Exposure to early prenatal stress (EPS) decreased placenta and embryo weight in males, but not females, exposed to the CTL diet. DHA-enrichment reversed the sex-specific decrease in placenta and embryo weight following EPS. Early prenatal exposure upregulated expression of genes associated with oxygen and nutrient transport, including hypoxia inducible factor 3α (HIF3α), peroxisome proliferator-activated receptor alpha (PPARα), and insulin like growth binding factor 1 (IGFBP1), in placenta of CTL diet males exposed to EPS. DHA-enrichment in EPS-exposed animals abrogated the male-specific upregulation of PPARα, HIF3α, and IGFBP1. Taken together, these studies suggest that maternal dietary DHA enrichment may buffer against maternal stress programming of sex-specific outcomes during early development.

scholarly journals Maternal DHA supplementation influences sex-specific disruption of placental gene expression following early prenatal stress

2020 ◽  
Author(s):  
Eldin Jašarević ◽  
Patrick M. Hecht ◽  
Kevin L. Fritsche ◽  
David C. Geary ◽  
Rocío M. Rivera ◽  
...  
Keyword(s):  
Prenatal Stress ◽  
Disease Risk ◽  
Control Diet ◽  
Hypoxia Inducible Factor ◽  
Peroxisome Proliferator ◽  
Omega 3 ◽  
Early Life Adversity ◽  
Peroxisome Proliferator Activated Receptor ◽  
Expression Of Genes ◽  
Dha Enrichment

Abstract Background: Early life adversity is a risk factor for early developmental perturbations and contributes to the presentation of neuropsychiatric disorders in adulthood. Neurodevelopmental disorders exhibit a strong sex-bias in susceptibility, presentation, onset and severity, although mechanisms conferring vulnerability are not well understood. Environmental perturbations during pregnancy, such as malnutrition or stress, have been associated with sex-specific reprogramming that contribute to increased disease risk in adulthood, whereby stress and nutritional insufficiency may be additive and further exacerbate poor offspring outcomes. Methods: To determine whether maternal docosahexanoic acid (DHA) supplementation effects offspring outcome following exposure to early prenatal stress (EPS), dams were fed nutritionally complete semi-purified diets that either contained adequate essential omega-6 (n-6) and omega-3 (n-3) fatty acids from corn and soy oils (control diet, CTL) or an experimental diet that was nutritionally-equivalent to the CTL diet, but contained 1% by weight DHA, a long-chain omega-3 fatty acid (22:6n-3). Dams were administered chronic variable stress during the first week of pregnancy (Embryonic day, E0.5 – 7.5). Developmental milestones were assessed at E 12.5. Results: Exposure to early prenatal stress (EPS) decreased placenta and embryo weight in males, but not females, exposed to CTL diet. DHA-enrichment reversed the sex-specific decrease in placenta and embryo weight following EPS. Early prenatal exposure upregulated expression of genes associated with oxygen and nutrient transport, including hypoxia inducible factor 3α (HIF3α), peroxisome proliferator-activated receptor alpha (PPARα), and insulin like growth binding factor 1 (IGFBP1), in placenta of CTL diet males exposed to EPS. DHA-enrichment in EPS-exposed animals abrogated male-specific upregulation of PPARα, HIF3α, and IGFBP1. Conclusions: This suggests that maternal dietary DHA enrichment may buffer against maternal stress programming of sex-specific outcomes during early development.

scholarly journals The Demethoxy Derivatives of Curcumin Exhibit Greater Differentiation Suppression in 3T3-L1 Adipocytes Than Curcumin: A Mechanistic Study of Adipogenesis and Molecular Docking

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1025
Author(s):  
Ahmed Alalaiwe ◽  
Jia-You Fang ◽  
Hsien-Ju Lee ◽  
Chun-Hui Chiu ◽  
Ching-Yun Hsu
Keyword(s):  
Molecular Docking ◽  
Fatty Acid Synthase ◽  
Structural Similarity ◽  
Mechanistic Study ◽  
Peroxisome Proliferator ◽  
Dependent Manner ◽  
Peroxisome Proliferator Activated Receptor ◽  
Enhancer Binding Protein ◽  
Underlying Mechanisms ◽  
Amp Activated Protein Kinase

Curcumin is a known anti-adipogenic agent for alleviating obesity and related disorders. Comprehensive comparisons of the anti-adipogenic activity of curcumin with other curcuminoids is minimal. This study compared adipogenesis inhibition with curcumin, demethoxycurcumin (DMC), and bisdemethoxycurcumin (BDMC), and their underlying mechanisms. We differentiated 3T3-L1 cells in the presence of curcuminoids, to determine lipid accumulation and triglyceride (TG) production. The expression of adipogenic transcription factors and lipogenic proteins was analyzed by Western blot. A significant reduction in Oil red O (ORO) staining was observed in the cells treated with curcuminoids at 20 μM. Inhibition was increased in the order of curcumin < DMC < BDMC. A similar trend was observed in the detection of intracellular TG. Curcuminoids suppressed differentiation by downregulating the expression of peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), leading to the downregulation of the lipogenic enzymes acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS). AMP-activated protein kinase α (AMPKα) phosphorylation was also activated by BDMC. Curcuminoids reduced the release of proinflammatory cytokines and leptin in 3T3-L1 cells in a dose-dependent manner, with BDMC showing the greatest potency. BDMC at 20 μM significantly decreased leptin by 72% compared with differentiated controls. Molecular docking computation indicated that curcuminoids, despite having structural similarity, had different interaction positions to PPARγ, C/EBPα, and ACC. The docking profiles suggested a possible interaction of curcuminoids with C/EBPα and ACC, to directly inhibit their expression.

scholarly journals Activation of Peroxisome Proliferator-activated Receptor α (PPARα) Suppresses Hypoxia-inducible Factor-1α (HIF-1α) Signaling in Cancer Cells

2012 ◽  
Vol 287 (42) ◽  
pp. 35161-35169 ◽  
Author(s):  
Jundong Zhou ◽  
Shuyu Zhang ◽  
Jing Xue ◽  
Jori Avery ◽  
Jinchang Wu ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Hypoxia Inducible Factor ◽  
Proteasome Inhibitors ◽  
Tube Formation ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Hypoxia Inducible Factor 1Α ◽  
Anticancer Properties ◽  
Pparγ Agonist ◽  
Expression And Activity

Activation of peroxisome proliferator-activated receptor α (PPARα) has been demonstrated to inhibit tumor growth and angiogenesis, yet the mechanisms behind these actions remain to be characterized. In this study, we examined the effects of PPARα activation on the hypoxia-inducible factor-1α (HIF-1α) signaling pathway in human breast (MCF-7) and ovarian (A2780) cancer cells under hypoxia. Incubation of cancer cells under 1% oxygen for 16 h significantly induced HIF-1α expression and activity as assayed by Western blotting and reporter gene analysis. Treatment of the cells with PPARα agonists, but not a PPARγ agonist, prior to hypoxia diminished hypoxia-induced HIF-1α expression and activity, and addition of a PPARα antagonist attenuated the suppression of HIF-1α signaling. Activation of PPARα attenuated hypoxia-induced HA-tagged HIF-1α protein expression without affecting the HA-tagged HIF-1α mutant protein level, indicating that PPARα activation promotes HIF-1α degradation in these cells. This was further confirmed using proteasome inhibitors, which reversed PPARα-mediated suppression of HIF-1α expression under hypoxia. Using the co-immunoprecipitation technique, we found that activation of PPARα enhances the binding of HIF-1α to von Hippel-Lindau tumor suppressor (pVHL), a protein known to mediate HIF-1α degradation through the ubiquitin-proteasome pathway. Following PPARα-mediated suppression of HIF-1α signaling, VEGF secretion from the cancer cells was significantly reduced, and tube formation by endothelial cells was dramatically impaired. Taken together, these findings demonstrate for the first time that activation of PPARα suppresses hypoxia-induced HIF-1α signaling in cancer cells, providing novel insight into the anticancer properties of PPARα agonists.

Clofibrate causes an upregulation of PPAR-α target genes but does not alter expression of SREBP target genes in liver and adipose tissue of pigs

2007 ◽  
Vol 293 (1) ◽  
pp. R70-R77 ◽  
Author(s):  
Sebastian Luci ◽  
Beatrice Giemsa ◽  
Holger Kluge ◽  
Klaus Eder
Keyword(s):  
Adipose Tissue ◽  
Target Genes ◽  
Regulatory Element ◽  
Control Diet ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Cholesterol Homeostasis ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Hepatic Expression

This study investigated the effect of clofibrate treatment on expression of target genes of peroxisome proliferator-activated receptor (PPAR)-α and various genes of the lipid metabolism in liver and adipose tissue of pigs. An experiment with 18 pigs was performed in which pigs were fed either a control diet or the same diet supplemented with 5 g clofibrate/kg for 28 days. Pigs treated with clofibrate had heavier livers, moderately increased mRNA concentrations of various PPAR-α target genes in liver and adipose tissue, a higher concentration of 3-hydroxybutyrate, and markedly lower concentrations of triglycerides and cholesterol in plasma and lipoproteins than control pigs ( P < 0.05). mRNA concentrations of sterol regulatory element-binding proteins (SREBP)-1 and -2, insulin-induced genes ( Insig) -1 and Insig-2, and the SREBP target genes acetyl-CoA carboxylase, 3-methyl-3-hydroxyglutaryl-CoA reductase, and low-density lipoprotein receptor in liver and adipose tissue and mRNA concentrations of apolipoproteins A-I, A-II, and C-III in the liver were not different between both groups of pigs. In conclusion, this study shows that clofibrate treatment activates PPAR-α in liver and adipose tissue and has a strong hypotriglyceridemic and hypocholesterolemic effect in pigs. The finding that mRNA concentrations of some proteins responsible for the hypolipidemic action of fibrates in humans were not altered suggests that there were certain differences in the mode of action compared with humans. It is also shown that PPAR-α activation by clofibrate does not affect hepatic expression of SREBP target genes involved in synthesis of triglycerides and cholesterol homeostasis in liver and adipose tissue of pigs.

scholarly journals Effects of NRF-1 and PGC-1α Cooperation on HIF-1α and Rat Cardiomyocyte Apoptosis Under Hypoxia

2021 ◽  
Author(s):  
Nan Niu ◽  
Hui Li ◽  
Xiancai Du ◽  
Chan Wang ◽  
Junliang Li ◽  
...  
Keyword(s):  
Hypoxia Inducible Factor ◽  
Regulatory Elements ◽  
Cardiomyocyte Apoptosis ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Rat Cardiomyocytes ◽  
Nuclear Respiratory Factor ◽  
Transcriptional Regulatory Elements ◽  
Nuclear Respiratory Factor 1 ◽  
Myocardial Hypoxia

Abstract Background: Hypoxia is a primary inducer of cardiomyocyte injury, its significant marker being hypoxia-induced cardiomyocyte apoptosis. Nuclear respiratory factor-1 (NRF-1) and hypoxia-inducible factor-1α (HIF-1α) are transcriptional regulatory elements implicated in multiple biological functions, including oxidative stress response. However, their roles in hypoxia-induced cardiomyocyte apoptosis remain unknown. The effect HIF-α, together with NRF-1, exerts on cardiomyocyte apoptosis also remains unclear. Methods: We established a myocardial hypoxia model and investigated the effects of these proteins on the proliferation and apoptosis of rat cardiomyocytes (H9C2) under hypoxia. Further, we examined the association between NRF-1 and HIF-1α to improve the current understanding of NRF-1 anti-apoptotic mechanisms. Results: The results show that NRF-1 and HIF-1α are important anti-apoptotic molecules in H9C2 cells under hypoxia, although their regulatory mechanisms differ. NRF-1 could bind to the promoter region of Hif1a and negatively regulate its expression. Additionally, HIF-1β exhibited competitive binding with NRF-1 and HIF-1α, demonstrating a synergism between NRF-1 and the peroxisome proliferator-activated receptor-gamma coactivator-1α. Conclusion: These results indicate that cardiomyocytes can regulate different molecular patterns to tolerate hypoxia, providing a novel methodological framework for studying cardiomyocyte apoptosis under hypoxia.

scholarly journals BH4 activates CaMKK2 and rescues the cardiomyopathic phenotype in rodent models of diabetes

2020 ◽  
Vol 3 (9) ◽  
pp. e201900619
Author(s):  
Hyoung Kyu Kim ◽  
Tae Hee Ko ◽  
In-Sung Song ◽  
Yu Jeong Jeong ◽  
Hye Jin Heo ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Therapeutic Potential ◽  
Cardiac Contractility ◽  
Camp Response Element Binding ◽  
Mitochondrial Activity ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Calcium Calmodulin Dependent ◽  
Element Binding Protein ◽  
Underlying Mechanisms

Diabetic cardiomyopathy (DCM) is a major cause of mortality/morbidity in diabetes mellitus patients. Although tetrahydrobiopterin (BH4) shows therapeutic potential as an endogenous cardiovascular target, its effect on myocardial cells and mitochondria in DCM and the underlying mechanisms remain unknown. Here, we determined the involvement of BH4 deficiency in DCM and the therapeutic potential of BH4 supplementation in a rodent DCM model. We observed a decreased BH4:total biopterin ratio in heart and mitochondria accompanied by cardiac remodeling, lower cardiac contractility, and mitochondrial dysfunction. Prolonged BH4 supplementation improved cardiac function, corrected morphological abnormalities in cardiac muscle, and increased mitochondrial activity. Proteomics analysis revealed oxidative phosphorylation (OXPHOS) as the BH4-targeted biological pathway in diabetic hearts as well as BH4-mediated rescue of down-regulated peroxisome proliferator-activated receptor-γ coactivator 1-α (PGC-1α) signaling as a key modulator of OXPHOS and mitochondrial biogenesis. Mechanistically, BH4 bound to calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2) and activated downstream AMP-activated protein kinase/cAMP response element binding protein/PGC-1α signaling to rescue mitochondrial and cardiac dysfunction in DCM. These results suggest BH4 as a novel endogenous activator of CaMKK2.

scholarly journals Effects of NRF-1 and PGC-1α Cooperation on HIF-1α and Rat Cardiomyocyte Apoptosis Under Hypoxia

2021 ◽  
Author(s):  
Nan Niu ◽  
Hui Li ◽  
Xiancai Du ◽  
Chan Wang ◽  
Junliang Li ◽  
...  
Keyword(s):  
Hypoxia Inducible Factor ◽  
Regulatory Elements ◽  
Cardiomyocyte Apoptosis ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Rat Cardiomyocytes ◽  
Nuclear Respiratory Factor ◽  
Transcriptional Regulatory Elements ◽  
Nuclear Respiratory Factor 1 ◽  
Myocardial Hypoxia

Abstract Hypoxia is a primary inducer of cardiomyocyte injury, its significant marker being hypoxia-induced cardiomyocyte apoptosis. Nuclear respiratory factor-1 (NRF-1) and hypoxia-inducible factor (HIF)-1α are transcriptional regulatory elements implicated in multiple biological functions, including oxidative stress response. However, their roles in hypoxia-induced cardiomyocyte apoptosis remain unknown. The effect HIF-α, together with NRF-1, exerts on cardiomyocyte apoptosis also remains unclear. We established a myocardial hypoxia model and investigated the effects of these proteins on the proliferation and apoptosis of rat cardiomyocytes (H9C2) under hypoxia. Further, we examined the association between NRF-1 and HIF-1α to improve the current understanding of NRF-1 anti-apoptotic mechanisms. The results showed that NRF-1 and HIF-1α are important anti-apoptotic molecules in H9C2 cells under hypoxia, although their regulatory mechanisms differ. NRF-1 could bind to the promoter region of Hif-1α and negatively regulate its expression. Additionally, HIF-1β exhibited competitive binding with NRF-1 and HIF-1α, demonstrating a synergism between NRF-1 and the peroxisome proliferator-activated receptor-gamma coactivator-1α. These results indicate that cardiomyocytes can regulate different molecular patterns to tolerate hypoxia, providing a novel methodological framework for studying cardiomyocyte apoptosis under hypoxia.

scholarly journals SIRT3 deficiency exacerbates fatty liver by attenuating the HIF1α-LIPIN 1 pathway and increasing CD36 through Nrf2

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Emma Barroso ◽  
Rosalía Rodríguez-Rodríguez ◽  
Mohammad Zarei ◽  
Javier Pizarro-Degado ◽  
Anna Planavila ◽  
...  
Keyword(s):  
Hepatic Steatosis ◽  
Target Genes ◽  
Hypoxia Inducible Factor ◽  
Redox Status ◽  
Acid Oxidation ◽  
Standard Diet ◽  
Peroxisome Proliferator ◽  
Lipid Uptake ◽  
Peroxisome Proliferator Activated Receptor ◽  
Vldl Receptor

Abstract Background Deficiency of mitochondrial sirtuin 3 (SIRT3), a NAD+-dependent protein deacetylase that maintains redox status and lipid homeostasis, contributes to hepatic steatosis. In this study, we investigated additional mechanisms that might play a role in aggravating hepatic steatosis in Sirt3-deficient mice fed a high-fat diet (HFD). Methods Studies were conducted in wild-type (WT) and Sirt3−/− mice fed a standard diet or a HFD and in SIRT3-knockdown human Huh-7 hepatoma cells. Results Sirt3−/− mice fed a HFD presented exacerbated hepatic steatosis that was accompanied by decreased expression and DNA-binding activity of peroxisome proliferator-activated receptor (PPAR) α and of several of its target genes involved in fatty acid oxidation, compared to WT mice fed the HFD. Interestingly, Sirt3 deficiency in liver and its knockdown in Huh-7 cells resulted in upregulation of the nuclear levels of LIPIN1, a PPARα co-activator, and of the protein that controls its levels and localization, hypoxia-inducible factor 1α (HIF-1α). These changes were prevented by lipid exposure through a mechanism that might involve a decrease in succinate levels. Finally, Sirt3−/− mice fed the HFD showed increased levels of some proteins involved in lipid uptake, such as CD36 and the VLDL receptor. The upregulation in CD36 was confirmed in Huh-7 cells treated with a SIRT3 inhibitor or transfected with SIRT3 siRNA and incubated with palmitate, an effect that was prevented by the Nrf2 inhibitor ML385. Conclusion These findings demonstrate new mechanisms by which Sirt3 deficiency contributes to hepatic steatosis. Graphical abstract

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