SIRT1 regulates hepatic vldlr levels.

BACKGROUND: Endoplasmic reticulum (ER) stress-mediated increases in the hepatic levels of the very low-density lipoprotein (VLDL) receptor (VLDLR) promote hepatic steatosis by increasing the delivery of triglyceride-rich lipoproteins to the liver. Here, we examined whether the NAD(+)-dependent deacetylase sirtuin 1 (SIRT1) regulates hepatic lipid accumulation by modulating VLDLR levels and the subsequent uptake of triglyceride-rich lipoproteins. METHODS: Rats fed with fructose in drinking water, Sirt1-/- mice, mice treated with the ER stressor tunicamycin with or without a SIRT1 activator, and human Huh-7 hepatoma cells transfected with siRNA or exposed to tunicamycin or different inhibitors were used. RESULTS: Hepatic SIRT1 protein levels were reduced, while those of VLDLR were upregulated in the rat model of metabolic dysfunction-associated steatotic liver disease (MASLD) induced by fructose-drinking water. Moreover, Sirt1-/- mice displayed increased hepatic VLDLR levels that were not associated with ER stress, but were accompanied by an increased expression of hypoxia-inducible factor 1α (HIF-1α)-target genes. The pharmacological inhibition or gene knockdown of SIRT1 upregulated VLDLR protein levels in the human Huh-7 hepatoma cell line, with this increase abolished by the pharmacological inhibition of HIF-1α. Finally, SIRT1 activation prevented the increase in hepatic VLDLR protein levels in mice treated with the ER stressor tunicamycin. CONCLUSIONS: Overall, these findings suggest that SIRT1 attenuates fatty liver development by modulating hepatic VLDLR levels.

GADD45A: With or without you.

The growth arrest and DNA damage inducible (GADD)45 family includes three small and ubiquitously distributed proteins (GADD45A, GADD45B, and GADD45G) that regulate numerous cellular processes associated with stress signaling and injury response. Here, we provide a comprehensive review of the current literature investigating GADD45A, the first discovered member of the family. We first depict how its levels are regulated by a myriad of genotoxic and non-genotoxic stressors, and through the combined action of intricate transcriptional, posttranscriptional, and even, posttranslational mechanisms. GADD45A is a recognized tumor suppressor and, for this reason, we next summarize its role in cancer, as well as the different mechanisms by which it regulates cell cycle, DNA repair, and apoptosis. Beyond these most well-known actions, GADD45A may also influence catabolic and anabolic pathways in the liver, adipose tissue and skeletal muscle, among others. Not surprisingly, GADD45A may trigger AMP-activated protein kinase activity, a master regulator of metabolism, and is known to act as a transcriptional coregulator of numerous nuclear receptors. GADD45A has also been reported to display a cytoprotective role by regulating inflammation, fibrosis and oxidative stress in several organs and tissues, and is regarded an important contributor for the development of heart failure. Overall data point to that GADD45A may play an important role in metabolic, neurodegenerative and cardiovascular diseases, and also autoimmune-related disorders. Thus, the potential mechanisms by which dysregulation of GADD45A activity may contribute to the progression of these diseases are also reviewed below.

GDF15 mediates the metabolic effects of PPARß/δ by activating AMPK.

Peroxisome proliferator-activated receptor ß/δ (PPARß/δ) activates AMP-activated protein kinase (AMPK) and plays a crucial role in glucose and lipid metabolism. Here, we examine whether PPARß/δ activation effects depend on growth differentiation factor 15 (GDF15), a stress response cytokine that regulates energy metabolism. Pharmacological PPARß/δ activation increases GDF15 levels and ameliorates glucose intolerance, fatty acid oxidation, endoplasmic reticulum stress, and inflammation, and activates AMPK in HFD-fed mice, whereas these effects are abrogated by the injection of a GDF15 neutralizing antibody and in Gdf15-/- mice. The AMPK-p53 pathway is involved in the PPARß/δ-mediated increase in GDF15, which in turn activates again AMPK. Consistently, Gdf15-/- mice show reduced AMPK activation in skeletal muscle, whereas GDF15 administration results in AMPK activation in this organ. Collectively, these data reveal a mechanism by which PPARß/δ activation increases GDF15 levels via AMPK and p53, which in turn mediates the metabolic effects of PPARß/δ by sustaining AMPK activation.

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

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. Video abstract.

SIRT3-mediated inhibition of FOS through histone H3 deacetylation prevents cardiac fibrosis and inflammation.

Sirtuin 3 (SIRT3) is a deacetylase that modulates proteins that control metabolism and protects against oxidative stress. Modulation of SIRT3 activity has been proposed as a promising therapeutic target for ameliorating metabolic diseases and associated cardiac disturbances. In this study, we investigated the role of SIRT3 in inflammation and fibrosis in the heart using male mice with constitutive and systemic deletion of SIRT3 and human cardiac AC16 cells. SIRT3 knockout mice showed cardiac fibrosis and inflammation that was characterized by augmented transcriptional activity of AP-1. Consistent with this, SIRT3 overexpression in human and neonatal rat cardiomyocytes partially prevented the inflammatory and profibrotic response induced by TNF-α. Notably, these effects were associated with a decrease in the mRNA and protein levels of FOS and the DNA-binding activity of AP-1. Finally, we demonstrated that SIRT3 inhibits FOS transcription through specific histone H3 lysine K27 deacetylation at its promoter. These findings highlight an important function of SIRT3 in mediating the often intricate profibrotic and proinflammatory responses of cardiac cells through the modulation of the FOS/AP-1 pathway. Since fibrosis and inflammation are crucial in the progression of cardiac hypertrophy, heart failure, and diabetic cardiomyopathy, our results point to SIRT3 as a potential target for treating these diseases.

Tissue Compatibility of SN-38-Loaded Anticancer Nanofiber Matrices.

Delivery of chemotherapy in the surgical bed has shown preclinical activity to control cancer progression upon subtotal resection of pediatric solid tumors, but whether this new treatment is safe for tumor-adjacent healthy tissues remains unknown. Here, Wistar rats are used to study the anatomic and functional impact of electrospun nanofiber matrices eluting SN-38-a potent chemotherapeutic agent-on several body sites where pediatric tumors such as neuroblastoma, Ewing sarcoma, and rhabdomyosarcoma arise. Blank and SN-38-loaded matrices embracing the femoral neurovascular bundle or in direct contact with abdominal viscera (liver, kidney, urinary bladder, intestine, and uterus) are placed. Foreign body tissue reaction to the implants is observed though no histologic damage in any tissue/organ. Skin healing is normal. Tissue reaction is similar for SN-38-loaded and blank matrices, with the exception of the hepatic capsule that is thicker for the former although within the limits consistent with mild foreign body reaction. Tissue and organ function is completely conserved after local treatments, as assessed by the rotarod test (forelimb function), hematologic tests (liver and renal function), and control of clinical signs. Overall, these findings support the clinical translation of SN-38-loaded nanofiber matrices to improve local control strategies of surgically resected tumors.

Peripheral and Central Effects of Memantine in a Mixed Preclinical Mice Model of Obesity and Familial Alzheimer's Disease.

There is growing evidence that obesity associated with type 2 diabetes mellitus (T2DM) and aging are risk factors for the development of Alzheimer's disease (AD). However, the molecular mechanisms through which obesity interacts with ß-amyloid (Aß) to promote cognitive decline remains poorly understood. Memantine (MEM), a N-methyl-D-aspartate receptor antagonist, is currently used for the treatment of AD. Nonetheless, few studies have reported its effects on genetic preclinical models of this neurodegenerative disease exacerbated with high-fat diet (HFD)-induced obesity. Therefore, the present research aims to elucidate the effects of MEM on familial AD HFD-induced insulin resistance and learning and memory impairment. Furthermore, it aspires to determine the possible underlying mechanisms that connect AD to T2DM. Wild type and APPswe/PS1dE9 mice were used in this study. The animals were fed with either chow or HFD until 6 months of age, and they were treated with MEM-supplemented water (30 mg/kg) during the last 12 weeks. Our study demonstrates that MEM improves the metabolic consequences produced by HFD in this model of familial AD. Behavioural assessments confirmed that the treatment also improves animals learning abilities and decreases memory loss. Moreover, MEM treatment improves brain insulin signalling upregulating AKT, as well as cyclic adenosine monophosphate response element binding (CREB) expression, and modulates the amyloidogenic pathway, which, in turn, reduced the accumulation of Aß. Moreover, this drug increases the activation of molecules involved with insulin signalling in the liver, such as insulin receptor substrate 2 (IRS2), which is a key protein regulating hepatic resistance to insulin. These results provide new insight into the role of MEM not only in the occurrence of AD treatment, but also in its potential application on peripheral metabolic disorders where Aß plays a key role, as is the case of T2DM.

Hepatic regulation of VLDL receptor by PPARß/δ and FGF21 modulates non-alcoholic fatty liver disease.

OBJECTIVE: The very low-density lipoprotein receptor (VLDLR) plays an important role in the development of hepatic steatosis. In this study, we investigated the role of Peroxisome Proliferator-Activated Receptor (PPAR)ß/δ and fibroblast growth factor 21 (FGF21) in hepatic VLDLR regulation. METHODS: Studies were conducted in wild-type and Pparß/δ-null mice, primary mouse hepatocytes, human Huh-7 hepatocytes, and liver biopsies from control subjects and patients with moderate and severe hepatic steatosis. RESULTS: Increased VLDLR levels were observed in liver of Pparß/δ-null mice and in Pparß/δ-knocked down mouse primary hepatocytes through mechanisms involving the heme-regulated eukaryotic translation initiation factor 2α (eIF2α) kinase (HRI), activating transcription factor (ATF) 4 and the oxidative stress-induced nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathways. Moreover, by using a neutralizing antibody against FGF21, Fgf21-null mice and by treating mice with recombinant FGF21, we show that FGF21 may protect against hepatic steatosis by attenuating endoplasmic reticulum (ER) stress-induced VLDLR upregulation. Finally, in liver biopsies from patients with moderate and severe hepatic steatosis, we observed an increase in VLDLR levels that was accompanied by a reduction in PPARß/δ mRNA abundance and DNA-binding activity compared with control subjects. CONCLUSIONS: Overall, these findings provide new mechanisms by which PPARß/δ and FGF21 regulate VLDLR levels and influence hepatic steatosis development.

Fenofibrate prevents the disruption of the outer blood retinal barrier through downregulation of NF-κB activity.

AIMS: There is clinical evidence that fenofibrate, a PPARα agonist, arrests the progression of diabetic macular edema (DME). However, the underlying mechanisms of this beneficial effect remain to be elucidated. We previously reported that fenofibric acid (FA), the active metabolite of fenofibrate, prevents the disorganization of tight junction proteins and the hyperpermeability provoked by the diabetic milieu in the retinal pigment epithelium (RPE). The aim of the present study was to evaluate whether this effect is mediated by inhibiting the proinflammatory transcription factor NF-κB, as well as the expression of several proinflammatory cytokines involved in the pathogenesis of DME. METHODS: Human RPE cells were cultured under standard conditions and under conditions leading to the disruption of the monolayer [IL-1ß (10 ng/ml)]. The effect of FA, QNZ (a NF-κB inhibitor), WY14643 (a PPARα agonist), and MK-866 (a PPARα antagonist) in the disruption of the monolayer was determined by dextran permeability and immunohistochemistry analyses. The effect of FA on NF-κB activity was assessed by EMSA and by NF-κB/p65 nuclear translocation analyses. The expression of cytokines (IL-6, IL-8, MCP-1) was measured by RT-PCR. RESULTS: FA prevented RPE monolayer disruption, and the consequent hyperpermeability induced by IL-1ß, through inhibition of NF-κB activity. This effect was due to PPARα activation and was associated with a significant downregulation of the expression of proinflammatory cytokines. CONCLUSIONS: Our findings suggest that the anti-inflammatory effects of FA through inhibition of NF-κB activity play a key role in the beneficial effect of fenofibrate for treating DME.

miR-146a targets Fos expression in human cardiac cells.

miR-146a is a microRNA whose transcript levels are induced in the heart upon activation of NF-κB, a transcription factor induced by pro-inflammatory molecules (such as TNF-α) that is strongly related to the pathogenesis of cardiac disorders. The main goal of this study consisted of studying new roles of miR-146a in cardiac pathological processes caused by the pro-inflammatory cytokine TNF-α. Our results demonstrate that miR-146a transcript levels were sharply increased in cardiac ventricular tissue of transgenic mice with specific overexpression of TNF-α in the heart, and also in a cardiomyocyte cell line of human origin (AC16) exposed to TNF-α. Among all the in silico predicted miR-146a target genes, Fos mRNA and protein levels notably decreased after TNF-α treatment or miR-146a overexpression. These changes correlated with a diminution in the DNA-binding activity of AP-1, the Fos-containing transcription factor complex. Interestingly, AP-1 inhibition was accompanied by a reduction in matrix metalloproteinase (MMP)-9 mRNA levels in human cardiac cells. The specific regulation of this MMP by miR-146a was further confirmed at the secretion and enzymatic activity levels, as well as after anti-miR-mediated miR-146a inhibition. The results reported here demonstrate that Fos is a direct target of miR-146a activity and that downregulation of the Fos-AP-1 pathway by miR-146a has the capacity to inhibit MMP-9 activity. Given that MMP-9 is an AP-1 target gene involved in cardiac remodeling, myocardial dysfunction and progression of heart failure, these findings suggest that miR-146a might be a new and promising therapeutic tool for treating cardiac disorders associated with enhanced inflammation in the heart.

PPAR-ß/δ activation promotes phospholipid transfer protein expression.

The peroxisome proliferator-activated receptor (PPAR)-ß/δ has emerged as a promising therapeutic target for treating dyslipidemia, including beneficial effects on HDL cholesterol (HDL-C). In the current study, we determined the effects of the PPAR-ß/δ agonist GW0742 on HDL composition and the expression of liver HDL-related genes in mice and cultured human cells. The experiments were carried out in C57BL/6 wild-type, LDL receptor (LDLR)-deficient mice and PPAR-ß/δ-deficient mice treated with GW0742 (10mg/kg/day) or a vehicle solution for 14 days. GW0742 upregulated liver phospholipid transfer protein (Pltp) gene expression and increased serum PLTP activity in mice. When given to wild-type mice, GW0742 significantly increased serum HDL-C and HDL phospholipids; GW0742 also raised serum potential to generate preß-HDL formation. The GW0742-mediated effects on liver Pltp expression and serum enzyme activity were completely abolished in PPAR-ß/δ-deficient mice. GW0742 also stimulated PLTP mRNA expression in mouse J774 macrophages, differentiated human THP-1 macrophages and human hepatoma Huh7. Collectively, our findings demonstrate a common transcriptional upregulation by GW0742-activated PPAR-ß/δ of Pltp expression in cultured cells and in mouse liver resulting in enhanced serum PLTP activity. Our results also indicate that PPAR-ß/δ activation may modulate PLTP-mediated preß-HDL formation and macrophage cholesterol efflux.

Enhanced fatty acid oxidation in adipocytes and macrophages reduces lipid-induced triglyceride accumulation and inflammation.

Lipid overload in obesity and type 2 diabetes is associated with adipocyte dysfunction, inflammation, macrophage infiltration, and decreased fatty acid oxidation (FAO). Here, we report that the expression of carnitine palmitoyltransferase 1A (CPT1A), the rate-limiting enzyme in mitochondrial FAO, is higher in human adipose tissue macrophages than in adipocytes and that it is differentially expressed in visceral vs. subcutaneous adipose tissue in both an obese and a type 2 diabetes cohort. These observations led us to further investigate the potential role of CPT1A in adipocytes and macrophages. We expressed CPT1AM, a permanently active mutant form of CPT1A, in 3T3-L1 CARΔ1 adipocytes and RAW 264.7 macrophages through adenoviral infection. Enhanced FAO in palmitate-incubated adipocytes and macrophages reduced triglyceride content and inflammation, improved insulin sensitivity in adipocytes, and reduced endoplasmic reticulum stress and ROS damage in macrophages. We conclude that increasing FAO in adipocytes and macrophages improves palmitate-induced derangements. This indicates that enhancing FAO in metabolically relevant cells such as adipocytes and macrophages may be a promising strategy for the treatment of chronic inflammatory pathologies such as obesity and type 2 diabetes.

Early alterations in energy metabolism in the hippocampus of APPswe/PS1dE9 mouse model of Alzheimer's disease.

The present study had focused on the behavioral phenotype and gene expression profile of molecules related to insulin receptor signaling in the hippocampus of 3 and 6 month-old APPswe/PS1dE9 (APP/PS1) transgenic mouse model of Alzheimer's disease (AD). Elevated levels of the insoluble Aß (1-42) were detected in the brain extracts of the transgenic animals as early as 3 months of age, prior to the Aß plaque formation (pre-plaque stage). By the early plaque stage (6 months) both the soluble and insoluble Aß (1-40) and Aß (1-42) peptides were detectable. We studied the expression of genes related to memory function (Arc, Fos), insulin signaling, including insulin receptor (Insr), Irs1 and Irs2, as well as genes involved in insulin growth factor pathways, such as Igf1, Igf2, Igfr and Igfbp2. We also examined the expression and protein levels of key molecules related to energy metabolism (PGC1-α, and AMPK) and mitochondrial functionality (OXPHOS, TFAM, NRF1 and NRF2). 6 month-old APP/PS1 mice demonstrated impaired cognitive ability, were glucose intolerant and showed a significant reduction in hippocampal Insr and Irs2 transcripts. Further observations also suggest alterations in key cellular energy sensors that regulate the activities of a number of metabolic enzymes through phosphorylation, such as a decrease in the Prkaa2 mRNA levels and in the pAMPK (Thr172)/Total APMK ratio. Moreover, mRNA and protein analysis reveals a significant downregulation of genes essential for mitochondrial replication and respiratory function, including PGC-1α in hippocampal extracts of APP/PS1 mice, compared to age-matched wild-type controls at 3 and 6 months of age. Overall, the findings of this study show early alterations in genes involved in insulin and energy metabolism pathways in an APP/PS1 model of AD. These changes affect the activity of key molecules like NRF1 and PGC-1α, which are involved in mitochondrial biogenesis. Our results reinforce the hypothesis that the impairments in both insulin signaling and energy metabolism precede the development of AD amyloidogenesis.

An overview of the crosstalk between inflammatory processes and metabolic dysregulation during diabetic cardiomyopathy.

Metabolic disorders such as obesity, insulin resistance and type 2 diabetes mellitus are all linked to cardiovascular diseases such as cardiac hypertrophy and heart failure. Diabetic cardiomyopathy in particular, is characterized by structural and functional alterations in the heart muscle of people with diabetes that finally lead to heart failure, and which is not directly attributable to coronary artery disease or hypertension. Several mechanisms have been involved in the pathogenesis of diabetic cardiomyopathy, such as alterations in myocardial energy metabolism and calcium signaling. Metabolic disturbances during diabetic cardiomyopathy are characterized by increased lipid oxidation, intramyocardial triglyceride accumulation, and reduced glucose utilization. Overall changes result in enhanced oxidative stress, mitochondrial dysfunction and apoptosis of the cardiomyocytes. On the other hand, the progression of heart failure and cardiac hypertrophy usually entails a local rise in cytokines in cardiac cells and the activation of the proinflammatory transcription factor nuclear factor (NF)-κB. Interestingly, increasing evidences are arising in the recent years that point to a potential link between chronic low-grade inflammation in the heart and metabolic dysregulation. Therefore, in this review we summarize recent new insights into the crosstalk between inflammatory processes and metabolic dysregulation in the failing heart during diabetes, paying special attention to the role of NF-κB and peroxisome proliferator activated receptors (PPARs). In addition, we briefly describe the role of the AMP-activated protein kinase (AMPK), sirtuin 1 (SIRT1) and other pathways regulating cardiac energy metabolism, as well as their relationship with diabetic cardiomyopathy.

[PPARß/δ Activation prevents hypertriglyceridemia caused by a high fat diet. Involvement of AMPK and PGC-1α-Lipin1-PPARα pathway]. / La activación de PPARß/δ previene la hipertrigliceridemia causada por una dieta rica en grasas. Implicación de la AMPK y de la vía PGC-1α-lipina1-PPAR.

INTRODUCTION: Excessive consume of hypercaloric and high in saturated fat food causes an atherogenic dyslipidemia. In this study we analyzed the effects of PPARß/δ activator GW501516 on the hypertriglyceridemia induced by a high-fat diet. METHODS: Male mice were randomized in three groups: control (standard chow), high fat diet (HFD, 35% fat by weight, 58% Kcal from fat) and high fat diet plus GW501516 (3mg/Kg/day). Treatment duration was three weeks. RESULTS: HFD-induced hypertriglyceridemia was accompanied by a reduction in hepatic levels of phospho-AMPK and in PGC-1α and Lipin1 mRNA levels. All these effects were reversed by GW501516 treatment. The lack of changes in phospho-AMPK levels after GW501516 treatment in HFD-fed animals could be the result of an increase in the AMP/ATP ratio. GW501516 treatment also increased Lipin1 protein levels in the nucleus, led to the amplification of the PGC-1α-PPARα pathway and increased PPARα DNA-binding activity, as well as the expression of PPARα-target genes involved in fatty acid oxidation. GW501516 also increased ß-hydroxibutirate plasmatic levels, a hepatic ß-oxidation end product. Finally, GW501516 increased the hepatic levels of the PPARα endogenous ligand 16:0/18:1-PC and the expression of the VLDL receptor. CONCLUSION: These data indicate that the hypotriglyceridemic effect of GW501516 in mice subjected to HFD-fed mice is accompanied by an increase in phospho-AMPK levels and the amplification of the PGC-1α-Lipin1-PPARα pathway.

Tau hyperphosphorylation and increased BACE1 and RAGE levels in the cortex of PPARß/δ-null mice.

The role of peroxisome proliferator activator receptor (PPAR)ß/δ in the pathogenesis of Alzheimer's disease has only recently been explored through the use of PPARß/δ agonists. Here we evaluated the effects of PPARß/δ deficiency on the amyloidogenic pathway and tau hyperphosphorylation. PPARß/δ-null mice showed cognitive impairment in the object recognition task, accompanied by enhanced DNA-binding activity of NF-κB in the cortex and increased expression of IL-6. In addition, two NF-κB-target genes involved in ß-amyloid (Aß) synthesis and deposition, the ß site APP cleaving enzyme 1 (Bace1) and the receptor for advanced glycation endproducts (Rage), respectively, increased in PPARß/δ-null mice compared to wild type animals. The protein levels of glial fibrillary acidic protein (GFAP) increased in the cortex of PPARß/δ-null mice, which would suggest the presence of astrogliosis. Finally, tau hyperphosphorylation at Ser199 and enhanced levels of PHF-tau were associated with increased levels of the tau kinases CDK5 and phospho-ERK1/2 in the cortex of PPARß/δ(-/-) mice. Collectively, our findings indicate that PPARß/δ deficiency results in cognitive impairment associated with enhanced inflammation, astrogliosis and tau hyperphosphorylation in the cortex.

Resveratrol induces nuclear factor-κB activity in human cardiac cells.

BACKGROUND: Resveratrol is a grape polyphenol that prevents cardiac hypertrophy and protects the heart from ischemic injury, metabolic dysregulation, and inflammatory processes in several murine models. METHODS AND RESULTS: The aim of this study was to investigate the effects of resveratrol on the inflammatory processes in human cardiac AC16 cells in order to gain a better understanding of its cardioprotective mechanisms in the human heart. Resveratrol induced the DNA-binding activity of the pro-inflammatory transcription factor NF-κB in AC16 cells, and exacerbated the increase caused by tumor necrosis factor-α (TNF-α). In accordance with this, resveratrol increased the expression of the pro-inflammatory genes ICAM-1 (intercellular adhesion molecule-1) and TNF-α. In contrast, resveratrol decreased the expression of pro-inflammatory genes IL-6 (interleukin-6) and MCP-1 (monocyte chemoattractant protein-1). Likewise, resveratrol also induced inflammation in rat neonatal cardiomyocytes, and in the heart of mice fed a standard chow diet supplemented with resveratrol (1g/kg diet) for four months. Western-blot analyses revealed that NF-κB p65 subunit levels were upregulated in an IκB-dependent manner in the nuclei of resveratrol-treated human cardiac cells. Finally, resveratrol activated the signal transducer and activator of transcription 3 (STAT3) signaling and induced the expression of its anti-apoptotic downstream effector Bcl-xL, both involved in the cardioprotective survival activating factor enhancement (SAFE) pathway. CONCLUSIONS: Resveratrol enhanced NF-κB activity in human and murine cardiac cells, in a process that coincided with the activation of STAT3 and anti-apoptotic downstream effectors. Therefore, activation of the SAFE pathway by resveratrol might be involved in the cardioprotective effects of this compound.

Alliin, a garlic (Allium sativum) compound, prevents LPS-induced inflammation in 3T3-L1 adipocytes.

Garlic (Allium sativum L.) has been used to alleviate a variety of health problems due to its high content of organosulfur compounds and antioxidant activity. The main active component is alliin (S-allyl cysteine sulfoxide), a potent antioxidant with cardioprotective and neuroprotective actions. In addition, it helps to decrease serum levels of glucose, insulin, triglycerides, and uric acid, as well as insulin resistance, and reduces cytokine levels. However its potential anti-inflammatory effect is unknown. We examined the effects of alliin in lipopolysaccharide- (LPS-) stimulated 3T3-L1 adipocytes by RT-PCR, Western blot, and microarrays analysis of 22,000 genes. Incubation of cells for 24 h with 100 µmol/L alliin prevented the increase in the expression of proinflammatory genes, IL-6, MCP-1, and Egr-1 in 3T3-L1 adipocytes exposed to 100 ng/mL LPS for 1 h. Interestingly, the phosphorylation of ERK1/2, which is involved in LPS-induced inflammation in adipocytes, was decreased following alliin treatment. Furthermore, the gene expression profile by microarrays evidentiate an upregulation of genes involved in immune response and downregulation of genes related with cancer. The present results have shown that alliin is able to suppress the LPS inflammatory signals by generating an anti-inflammatory gene expression profile and by modifying adipocyte metabolic profile.