Expression Of Fatty Acid Binding Protein Research Articles

Pioglitazone Increases Blood-Brain Barrier Expression of Fatty Acid-Binding Protein 5 and Docosahexaenoic Acid Trafficking into the Brain.

Brain levels of docosahexaenoic acid (DHA), an essential cognitively beneficial fatty acid, are reduced in Alzheimer's disease (AD). We have demonstrated in an AD mouse model that this is associated with reduced blood-brain barrier (BBB) transport of DHA and lower expression of the key DHA-trafficking protein, fatty acid-binding protein 5 (FABP5). This study focused on assessing the impact of activating peroxisome proliferator-activated receptor (PPAR) isoforms on FABP5 expression and function at the BBB. Using immortalized human brain endothelial (hCMEC/D3) cells, a 72 h treatment with the PPARα agonist clofibrate (100 μM), and PPARβ/δ agonists GW0742 (1 μM) and GW501506 (0.5 μM), did not affect FABP5 protein expression. In contrast, the PPARγ agonists rosiglitazone (5 μM), pioglitazone (25 μM), and troglitazone (1 μM) increased FABP5 protein expression by 1.15-, 1.18-, and 1.24-fold in hCMEC/D3 cells, respectively, with rosiglitazone and pioglitazone also increasing mRNA expression of FABP5. In line with an increase in FABP5 expression, pioglitazone increased 14C-DHA uptake into hCMEC/D3 cells 1.20- to 1.33-fold over a 2 min period, and this was not associated with increased expression of membrane transporters involved in DHA uptake. Furthermore, treating male C57BL/6J mice with pioglitazone (40 mg/kg/day for 7 days) led to a 1.79-fold increase in BBB transport of 14C-DHA over 1 min, using an in situ transcardiac perfusion technique, which was associated with a 1.82-fold increase in brain microvascular FABP5 protein expression. Overall, this study demonstrated that PPARγ can regulate FABP5 at the BBB and facilitate DHA transport across the BBB, important in restoring brain levels of DHA in AD.

Impacts of Sex and Exposure Duration on Gene Expression in Zebrafish Following Perfluorooctane Sulfonate Exposure.

Perfluorooctane sulfonate (PFOS) is a member of the anthropogenic class of perfluorinated alkyl acids (PFAAs) and one of the most frequently detected PFAAs in water, humans, mammals, and fish around the world. The zebrafish (Danio rerio) is a small freshwater fish considered an appropriate vertebrate model for investigating the toxicity of compounds. Previous investigations showed tissue-specific bioaccumulation and alterations in the expression of fatty acid-binding proteins (fabps) in male and female zebrafish, potentially due to interactions between PFAA and fatty acid transporters. In addition, a number of neurological impacts have been reported as a result of human and animal exposure to PFAAs. Therefore, the present comprehensive study was designed to investigate whether PFOS exposure affects the expression of genes associated with fatty acid metabolism (fabp1a, fabp2, and fabp10a) in zebrafish liver, intestine, heart, and ovary and genes involved in the nervous system (acetylcholinesterase, brain-derived neurotrophic factor, choline acetyltransferase, histone deacetylase 6, and nerve growth factor) in brain and muscle. The results indicate alterations in expression of genes associated with fatty acid metabolism and neural function that vary with both exposure concentration and sex. In addition, our findings highlight that expression of these genes differs according to exposure duration. The present results extend the knowledge base on PFOS effects to other tissues less often studied than the liver. The findings of the present investigation provide a basis for future studies on the potential risks of PFOS as one of the most abundant PFAAs in the environment. Environ Toxicol Chem 2020;39:437-449. © 2019 SETAC.

Expression of key myogenic, fibrogenic and adipogenic genes in Longissimus thoracis and Masseter muscles in cattle

Adipogenesis, myogenesis and fibrogenesis are related processes that can contribute to meat quality. Therefore, extending the knowledge of these processes would facilitate the identification of molecular markers that predict intramuscular fat accretion. The main purpose of this work, based on previous results, was to further study the expression of key genes related to adipogenic, myogenic, fibrogenic processes and some cytokines in Longissimus thoracis (LT) and Masseter (MS) muscles of Pirenaica and Holstein young bulls. Longissimus thoracis and MS muscles from Pirenaica (n = 4) and Spanish Holstein (n = 4) were sampled for proximate analysis, determination of adipocyte size distribution and expression of key candidate genes. Fat percentage was lower in LT than in MS muscle in Pirenaica young bulls (P = 0.023) and was higher in LT muscle in Holstein than in Pirenaica young bulls (P = 0.007). Gene expression analysis revealed that the mRNA level of myogenic differentiation 1 (MYOD) was higher in LT than in MS muscles in both groups of animals (P < 0.001) and that myostatin (MSTN) expression was also higher in LT than in MS muscle in Holstein bulls (P = 0.001). On the other hand, MSTN and PPARG showed higher expression in LT and MS in Pirenaica young bulls (P = 0.026), while the expression of fatty acid-binding protein 4 (FABP4) was higher in Holstein young bulls, also in both muscles (P < 0.001). The results suggested that the development of intramuscular adipose depot was directly related to the expression of adipogenic genes, such as FABP4, but inversely related to the expression of the cytokine MSTN and the myogenic gene MYOD, genes which showed a muscle-specific expression.

24 Validation of swine enteroids as a model to study Lawsonia intracellularis pathogenesis

Abstract Lawsonia intracellularis is an obligate intracellular bacterium that causes proliferative ileitis, an enteric disease that costs more than $100 million annually to the US swine industry. Information about L. intracellualris pathogenesis is scarce due to lack of suitable in vitro models to study the infection-induced proliferative changes. L. intracellularis infection of the swine ileum has been shown to decrease the number of mucin-producing goblet cells and increase cell proliferation along with amplification of transient amplifying cells demonstrated by the expression of SOX9. The objective of this study was to validate the use of swine enteroids (three dimensional structures derived from adult intestinal stem cells) as a model to study the intestinal epithelial changes caused by L. intracellularis infection. Swine enteroids plated on transwell plate inserts to cover the surface area were infected with 108 L. intracellularis organisms in culture media per well and incubated at 37⁰C with atmospheric conditions of 8.0% oxygen, 8.8% carbon dioxide, and 83.2% nitrogen. Infected enteroids were collected after 7 days and gene expression levels of mucin 2 (MUC2), enterocyte marker fatty acid binding protein (FABP), endocrine marker chromogranin A (CGA), intestinal epithelium marker villin 1 (VIL1), paneth cell marker lysozyme (LYZ), proliferating cell nuclear antigen (PCNA) and SOX9 were measured. The expression of FABP and LYZ in L. intracellularis infected swine enteroids decreased by 50% and 20% respectively and the expression of SOX9 increased by 50%, with no significant changes for the levels of VIL1 and CGA. The changes observed in the infected swine enteroids reflect the profile of gene expression observed in L. intracellularis infected ileal tissue. Therefore, swine enteroids are a suitable in vitro system to study the dynamics of cell differentiation and proliferation of the intestinal epithelium induced by L. intracellularis infection.

Expression and correlation of Chemerin and FABP4 in peripheral blood of gestational diabetes mellitus patients.

Expression and correlation of Chemerin and fatty acid-binding protein 4 (FABP4) in peripheral blood of gestational diabetes mellitus (GDM) patients were investigated. Sixty patients with GDM from March 2018 to March 2019 in the People's Hospital of Zhangqiu Area were selected as the study group (SG) and another 50 healthy pregnant women corresponding to their age and pregnancy were selected as the control group (CG). Enzyme linked immunosorbent assay (ELISA) was used to detect the expression of Chemerin and FABP4 in serum. Receiver operating characteristic (ROC) curve was used to evaluate the diagnostic value of Chemerin and FABP4 in peripheral blood for GDM patients. Pearson's correlation coefficient was used to analyze the correlation between Chemerin and FABP4 and the correlation between Chemerin and inflammatory factors such as interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). Expression of Chemerin and FABP4 in peripheral blood of GDM patients were significantly higher than those in CG. The AUC of GDM patients diagnosed with Chemerin and FABP4 in peripheral blood was 0.820 and 0.814, while the AUC of GDM patients diagnosed with Chemerin combined with FABP4 in peripheral blood was 0.904. Expression of inflammatory factors IL-6 and TNF-α in the SG were significantly higher than those in the CG. Chemerin in the SG was positively correlated with FABP4 and positively correlated with inflammatory factors IL-6 and TNF-α. Patients with advanced age (≥35 years), family history of diabetes, hyperlipidemia, high pre-pregnancy BMI, high fasting blood glucose, high Chemerin and high FABP4 expression have high risk of GDM. In conclusion, Chemerin and FABP4 were upregulated in the peripheral blood of GDM patients. There was a positive correlation between the two and a positive correlation with the inflammatory factors IL-6 and TNF-α.

Effect of Dietary Calcium on Adipogenesis Program and Its Role in Adipocyte Dysfunction in Male Wistar Rats

Dietary calcium influences obesity-related adipocyte dysfunction by modulating body weight. The molecular mechanism behind this weight management is under intense investigation. In the present study, the authors investigated the effect of dietary calcium on peroxisome proliferator-activated receptor-γ (PPAR-γ)-mediated adipogenesis program and its role in adipocyte dysfunction by measuring the inflammatory and oxidative markers within the adipose tissue of male albino rats. Healthy male rats were fed with a control diet based on AIN-93, and either low-calcium (0.25%) or high-calcium (1.0%) diet for 90 days. A significant inverse (p < 0.05) relationship exists between the calcium intake and anthropometric parameters like adipose tissue mass and body weight. Adipose tissue PPAR-γ activity along with its downstream enzyme activities like glyceraldehydes 3 phosphate dehydrogenase, lipoprotein lipase as well as the protein expression of fatty acid-binding protein 4 and calcium-sensing receptor were significantly increased (p < 0.05) in the low-calcium-fed rats which in turn promoted the adipogenesis program. At the same time, protein expression of inflammatory markers like tumor necrosis factor-α and interleukin-6 and oxidative stress markers like lipid peroxidation and protein carbonylation were significantly increased (p < 0.05) in low-calcium-fed rats. These deleterious effects were suppressed by the high-calcium diet by preventing the activation of the adipogenesis program. Thus, the present study showed the involvement of dietary calcium against the PPAR-γ-mediated adipogenesis program as well as its role in adipocyte dysfunction by regulating the inflammatory and oxidative stress.

Supplementing calcium salts of soybean oil to beef steers early in life to enhance carcass development and quality1.

This study evaluated the effects of supplementing Ca salts of soybean oil (CSSO) to beef steers at 2 mo of age via creep-feeding, and/or during a 40-d preconditioning period on performance and carcass development responses. A total of 64 steers were enrolled in this study over 2 yr (32 steers per year), with 4 periods each year: creep-feeding (CF; day 0 to 60), preweaning (day 61 to weaning on day 124 and 127 of year 1 and 2, respectively), preconditioning (PC; day 132 to 172 in year 1 and day 135 to 175 of year 2), and feedlot (feedlot arrival to slaughter, day 173 to 378 in year 1 and day 176 to 385 in year 2). On day 0 steers were ranked by body weight (BW) and age (114 ± 4 kg of BW; 66.1 ± 0.9 d of age) and allocated to 1 of 16 pens. Pens were randomly assigned to receive CSSO during CF (80 g/d per steer) and/or PC (150 g/d per steer) in a 2 × 2 factorial arrangement of treatments. During CF and PC, nonsupplemented steers (CON) were provided an isolipidic prilled saturated fat supplement. Steer BW was recorded on day 0, 60, at weaning, and prior to feedlot shipping. Carcass traits were recorded upon slaughter. On day 0, 60, at weaning, prior to feedlot shipping, and during the feedlot period, blood samples were collected and longissimus muscle (LM) biopsies were collected. On day 60, steers that received CSSO during CF had greater (P < 0.01) plasma concentrations of linoleic and ω-6 compared with CON (CF treatment × day; P ≤ 0.05). Steers that received CSSO during PC had greater (P < 0.01) plasma concentrations of linoleic, ω-6, and total fatty acids compared with CON at feedlot shipping (PC treatment × day; P ≤ 0.05). A PC treatment × day interaction was also detected (P = 0.04) for mRNA expression of peroxisome proliferator-activated receptor gamma (PPAR-γ), which was greater (P = 0.04) at feedlot shipping for steers receiving CSSO during PC. Interactions between CF treatment × day were detected (P ≤ 0.01) for mRNA expression of adipocyte fatty acid-binding protein, fatty acid synthase, PPAR-γ, and stearoyl-CoA desaturase, which were greater (P ≤ 0.02) in the feedlot in steers receiving CSSO during CF. No treatment differences were detected for (P ≥ 0.18) performance or carcass traits, including marbling and backfat thickness. Results from this study suggest that supplementing CSSO to suckled beef steers via creep-feeding upregulated mRNA expression of the adipogenic genes investigated herein later in life. These outcomes, however, were not translated into improved carcass quality.

Isolation and characterization of a novel oligomeric proanthocyanidin with significant anti-cancer activities from grape stems (Vitis vinifera)

Novel proanthocyanidin fractions from grape stem extracts were purified using Amberlite XAD-1180N, Sephadex-LH-20, Toyopearl HW40F and reverse phase high-performance liquid chromatography. Two key compounds were estimated as epigallocatechin-(epicatechin)7 gallate using electron-spray ionization time-of-flight mass spectrometry. Epigallocatechin-(epicatechin)7 gallate (compound 1) showed significant anti-cancer activity in PC-3 prostate cancer cells. In particular, compound 1 suppressed the gene expression of fatty acid-binding protein 5 (FABP5), which is involved in promoting cell proliferation and metastasis in prostate cancer cells.

Pterostilbene Inhibits Adipocyte Conditioned-Medium-Induced Colorectal Cancer Cell Migration through Targeting FABP5-Related Signaling Pathway.

Pterostilbene (PTS) is a phenolic compound with diverse pharmacologic activities. However, its potential for inhibiting obesity-related colorectal cancer (CRC) remains unclear. Our study evaluated the mechanism of inhibitory effects of PTS on adipocyte conditioned-medium (aCM)-induced malignant transformation in HT-29 colorectal adenocarcinoma cells. The results demonstrated that PTS could downregulate the expression of aCM-induced fatty acid-binding protein 5 (FABP5) and prometastatic factors such as vascular endothelial growth factor, matrix metalloproteinase-2 (MMP2), MMP9, and extracellular tumor necrosis factor α via inhibiting aCM-induced nuclear factor-kappa B (NF-κB), β-catenin, and peroxisome proliferator-activated receptor γ (PPAR-γ). Moreover, PTS can suppress aCM-stimulated phosphoinositide 3-kinase (PI3K), protein kinase B (Akt), p38 mitogen-activated protein kinase (p38 MAPK), extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinases 1/2 (JNK 1/2) signaling pathways activation that are upstream of NF-κB, β-catenin, and PPAR-γ. Therefore, we suggest that PTS could alleviate adiposity-induced metastasis in CRC via inhibiting cell migration through downregulating FABP5 gene expression.

Association of A-FABP gene polymorphism and mRNA expression with intramuscular fat content (IMF) in Baicheng-You chicken.

This study aims to assess the association of polymorphisms and mRNA expression of adipocyte-type fatty acid-binding protein (A-FABP) with intramuscular fat (IMF) in the breast muscle (BM) and leg muscle (LM) of Baicheng-You chickens (BYCs). A total of 180 chickens, including sixty black Baicheng-You chickens (BBYCs), sixty silky Baicheng-You chickens (SBYCs) and sixty white Baicheng-You chickens (WBYCs), were reared from 1 to 120day. A polymerase chain reaction-single-strand conformation polymorphism strategy (PCR-SSCP) was used to detect the polymorphism of the A-FABP gene in the first exon, and the C51T silent mutational site was found. The IMF content with the AA genotype was significantly higher than that with the AG genotype (p=0.0473) in the LM of WBYC. Thus, this site could be taken as a molecular marker in selecting a higher IMF content of LM in WBYC. A-FABP gene mRNA expression in the BM and LM of BYCs was detected, and a significant positive correlation was observed in the LM of WBYC. These findings provide fundamental data that might be useful in further study of the role of the A-FABP gene in IMF content and fatty metabolism in chickens.

Hepatopancreas and ovarian transcriptome response to different dietary soybean lecithin levels in Portunus trituberculatus

Ovaries (O) are specialized tissues that play critical roles in producing oocytes and hormones. The crustacean hepatopancreas (H) is a metabolic organ that plays important functions including absorption, storage of nutrients and vitellogenesis during growth and ovarian development. However, genetic information on the biological functions of the crustacean ovaries and hepatopancreas are limited. This study compared the transcriptome in the ovary and the hepatopancreas of female P. trituberculatus fed two different diets containing 0% (SL0) and 4% soybean lecithin (SL4), respectively during the growth and ovarian maturation stages by Illumina HiSeq4000 sequencer. The differences between ovary and hepatopancreas of P. trituberculatus were also compared at transcriptional level. A total of 55,667 unigenes were obtained with mean length of 962 bps across the four treatment groups (SL0_O, SL4_O, SL0_H and SL4_H). In ovary, there were 257 differentially expressed genes (DEGs) between SL0_O and SL4_O, with 145 down- and 112 up-regulated genes in the SL4_O group. Candidate genes involved in ovarian development were detected in SL4_H group. In hepatopancreas, 146 DEGs were found between SL0_H and SL4_H, including 43 down- and 103 up-regulated genes in the SL4_H group. The specific DEGs were mainly involved with lipid related metabolism pathways, including fat digestion and absorption, PPAR signaling pathway and insulin resistance. 14,725 DEGs were found in the comparison between SL0_O and SL4_H, including 7250 up- and 7475 down-regulated genes in the SL4_H group. The specific DEGs were mainly involved with lipid (fat digestion and absorption, linoleic acid metabolism), hormone (steroid hormone biosynthesis, ovarian steroidogenesis, etc), and amino acid (phenylalanine metabolism, arginine biosynthesis, tyrosine) related metabolism pathways. Crabs fed the SL4 diet exhibited higher gene expression of cryptocyanin 1 (cc1), cryptocyanin 2 (cc2) and neuroparsin 1 (np1) in hepatopancreas and ovarian than those fed the SL0 diet, however, crab fed SL4 diet showed higher gene expression of fatty acid-binding protein 1 (fabp1), vitellogenin (vtg) and Delta-6 desaturase-like protein (fadsd6) in hepatopancreas than those fed the SL0 diet. Moreover, crabs fed the SL0 diet had lower gene expression of vtg, extracellular copper‑zinc superoxide dismutase (cuznsod) and estrogen sulfotransferase (ests) in ovary compared to those fed the diet containing 4% soybean lecithin. These results might provide important clues with respect to elucidating the molecular mechanisms underlying the regulation of phospholipid on the gonadal development and lipid metabolism of P. trituberculatus.

Transcriptional regulation of bovine elongation of very long chain fatty acids protein 6 in lipid metabolism and adipocyte proliferation.

The elongation of very long chain fatty acids protein 6 (ELOVL6) gene encodes a key enzyme that plays a role in lipogenesis through the catalytic elongation of both saturated and monounsaturated fatty acids. Previous studies have described the high expression of bovine ELOVL6 in adipose tissues. However, transcriptional regulation and the functional role of ELOVL6 in lipid metabolism and adipocyte proliferation remain unexplored. Here, a 1.5 kb fragment of the 5'-untranslated region promoter region of ELOVL6 was amplified from the genomic DNA of Qinchuan cattle and sequenced. The core promoter region was identified through unidirectional 5'-end deletion of the promoter plasmid vector. In silico analysis predicted important transcription factors that were then validated through site-directed mutation and small interfering RNA interference with an electrophoretic mobility shift assay. We found that the binding of KLF6 and PU.1 transcription factors occurred in the region -168/+69. Both perform a vital regulatory function in the transcription of bovine ELOVL6. Overexpression of ELOVL6 significantly upregulated the expression of peroxisome proliferator activated receptor γ (PPARγ), but inhibited the expression of fatty acid-binding protein 4 (FABP4), while silencing of ELOVL6 negatively regulated the messenger RNA expression level of PPARγ, FABP4, ACSL, and FATP1. In addition, ELOVL6 promotes adipocyte proliferation by regulating the cell-cycle genes' expression. Taken together, these findings provide useful information about the transcriptional regulation and functional mechanisms of bovine ELOVL6 in lipid metabolism and adipocyte proliferation in Qinchuan cattle.

Fatty acid-binding protein 3 contributes to ischemic heart injury by regulating cardiac myocyte apoptosis and MAPK pathways.

Fatty acid-binding protein 3 (FABP3), a low-molecular-weight protein, participates in lipid transportation, storage, signaling transduction, oxidation, and transcription regulation. Here, we investigated the expression and function of FABP3 in ischemic heart diseases and explored the mechanisms by which FABP3 affected remodeling after myocardial infarction (MI). We showed that ischemic or hypoxic conditions upregulated FABP3 expression in vivo and in vitro. Notably, overexpression of FABP3 induced more myocyte apoptosis in the infarction and border areas and aggravated cardiac dysfunction, with lower left ventricular ejection fraction. Meanwhile, overexpression of FABP3 drastically promoted death and apoptosis of neonatal rat ventricular cardiomyocytes under hypoxia. Furthermore, deficiency of FABP3 exerted protective effects against ischemic heart injuries by decreasing cardiac myocyte apoptosis and heart remodeling after MI. We found that overexpression of FABP3 upregulated the phosphorylation of MAPK signaling pathway and decreased phosphorylated Akt levels, which may account for the augmentation of apoptosis and remodeling after MI. To the best of our knowledge, this is the first study to demonstrate that deficiency of FABP3 would protect cardiac myocytes from apoptosis and alleviate cardiac remodeling after MI, suggesting FABP3 as a potential target to preserve cardiac function after MI. NEW & NOTEWORTHY It is an undisputable fact that myocyte apoptosis plays a crucial role in cardiac remodeling and the development of heart failure after myocardial infarction. Here, fatty acid-binding protein 3 deficiency improved myocardial structural remodeling and function by decreasing cell apoptosis and regulating MAPK signaling pathways. We suppose that fatty acid-binding protein 3 may be regarded as a potential intervention approach to preserve cardiomyocytes during myocardial infarction.

Effects of FABP knockdown on flight performance of the desert locust, Schistocerca gregaria.

During migratory flight, desert locusts rely on fatty acids as their predominant source of energy. Lipids mobilized in the fat body are transported to the flight muscles and enter the muscle cells as free fatty acids. It has been postulated that muscle fatty acid binding protein (FABP) is needed for the efficient translocation of fatty acids through the aqueous cytosol towards mitochondrial β-oxidation. To assess whether FABP is required for this process, dsRNA was injected into freshly emerged adult males to knock down the expression of FABP. Three weeks after injection, FABP and its mRNA were undetectable in flight muscle, indicating efficient silencing of FABP expression. At rest, control and treated animals exhibited no morphological or behavioral differences. In tethered flight experiments, both control and treated insects were able to fly continually in the initial, carbohydrate-fueled phase of flight, and in both groups, lipids were mobilized and released into the hemolymph. Flight periods exceeding 30min, however, when fatty acids become the main energy source, were rarely possible for FABP-depleted animals, while control insects continued to fly for more than 2 h. These results demonstrate that FABP is an essential element of skeletal muscle energy metabolism in vivo.

Rotenoisin A is a novel anti-adipogenic compound

The purpose of this study was to investigate the mechanisms underlying the inhibitory effects of rotenoisin A on adipogenesis in 3T3-L1 preadipocytes. 3T3-L1 cells were treated with rotenoisin A for 8 days after the induction of differentiation. Oil-red O staining showed that rotenoisin A significantly inhibited DMI-induced lipid accumulation and adipocyte differentiation. We found that rotenoisin A treatment of 3T3-L1 preadipocytes significantly reduced the mRNA and protein levels of the key adipocyte-specific transcription factors C/EBPβ, C/EBPα, and PPARγ and markedly inhibited the expression of fatty acid-binding protein (aP2), fatty acid synthase (FAS), and lipoprotein lipase (LPL). Furthermore, we observed that rotenoisin A substantially increased the phosphorylation of AMP-activated protein kinase (AMPK) and its downstream target phosphorylated acetyl CoA carboxylase (ACC). However, co-treatment with Compound C, an AMPK inhibitor, reversed the rotenoisin A-induced inhibition of the expression of the adipogenic transcription factors C/EBPα and PPARγ and decreased the levels of phosphorylated AMPK in differentiated 3T3-L1 cells. These results demonstrated that the anti-adipogenesis mechanism involves the down-regulation of critical adipogenic transcription factors, including C/EBPβ, C/EBPα, and PPARγ, through activation of the AMPK signaling pathway by rotenoisin A.

Altered epidermal fatty acid-binding protein expression in hepatocellular carcinoma predicts unfavorable outcomes.

ObjectiveHepatocellular carcinoma (HCC) is a rapidly proliferating malignancy that requires large amounts of fatty acids to synthesize cellular membranes and provide energy. Epidermal fatty acid-binding protein (EFABP) is uniquely expressed in epidermal cells, but its role and expression in HCC are not clear.Subjects and methodsA total of 804 HCC specimens were collected to construct a tissue microarray (TMA) and for immunohistochemistry (IHC) analysis. The relationship between EFABP expression and clinical features of patients with HCC was analyzed.ResultsThe EFABP IHC score for HCC tissue was 0.76±0.69, being significantly higher than that for matched nontumorous tissue (0.48±0.55; P<0.001). Using the median IHC score (ie, 0.8) in the tumorous tissue, a high level of EFABP expression was found in 57.3% (461/804) of the cases. Patients with HCC displaying high EFABP expression had poorer tumor differentiation (P=0.029), more vascular invasion (P=0.006), and a higher proportion of late TNM stage disease (P=0.042). Kaplan–Meier analysis revealed that the patients with high EFABP expression had significantly worse outcomes in terms of overall survival (P=0.003), worse disease-free survival (P=0.021), and a higher probability of recurrence (P=0.014). Multivariate analysis indicated that EFABP expression was an independent prognostic variable for overall survival (P=0.021) and disease-free survival (P=0.044). For HCC recurrence, only vascular invasion (P=0.020) and EFABP expression (P=0.026) were independent risk factors.ConclusionOur data revealed that EFABP expression was increased in HCC samples. High EFABP expression was correlated with shorter survival times in patients with HCC and served as an independent factor for worse outcomes. Our study therefore provides a promising bio-marker for the prognostic prediction of HCC and a potential therapeutic target for the disease.

Acrylamide induces adipocyte differentiation and obesity in mice

Obesity is a critical risk factor for various diseases including type II diabetes, cerebral infarction, cardiovascular diseases, and various cancers. Acrylamide (ACR) is present in wide range of foods, including fried potato products, root vegetables, bakery products, chips, cakes, cereals, and coffee. In this study, ACR treatment dramatically increased the accumulation of lipid droplets. We also examined expression levels of peroxisome proliferator-activated receptors γ (PPARγ), CCAAT enhancer binding protein α (c/EBPα), and CCAAT enhancer binding protein β (c/EBPβ) as adipogenic transcription factors for adipocyte differentiation. They were dose-dependently increased by treatment of ACR. Moreover, effects of ACR on mitogen-activated protein kinases (MAPKs) and 5′ AMP-activated protein kinase (AMPK)-Acetyl-CoA carboxylase (ACC) activation were investigated. Results also showed that ACR induced phosphorylation of MAPKs and AMPK-ACC. ACR also induced expression of adipocyte fatty acid-binding protein (aP2), lipoprotein lipase (LPL), sterol regulatory element-binding protein (SREBP)-1c, and fatty acid synthase (FAS). Exposure of ACR to high fat diet (HFD)-fed mice significantly increased body weight, organ weight, and fat mass of mice. Collectively, these result showed that ACR can act as an enhancer of adipocyte. Therefore, we suggest that up-regulation of the adipogenesis by ACR may be related to the regulation of the MAPKs and AMPK-ACC pathway.

Profile of cardiac lipid metabolism in STZ-induced diabetic mice

BackgroundLipotoxicity contributes to diabetic myocardial disease. In this study, we investigated the lipid species contributing to lipotoxicity and the relationship with peroxisomal β-oxidation in the heart of diabetic mice.MethodsMale C57BL/6 mice were randomly divided into a Diabetic group (intraperitoneal injection of STZ) and a Control group (saline). Cardiac function indexes [ejection fraction (EF%) and fractional shortening (FS%)] were evaluated by echocardiography. Morphological changes in the myocardial tissues and mitochondria were assessed by electron microscopy following hematoxylin and eosin staining. Blood myocardial injury indexes and lipids were measured using an automatic biochemical analyzer. Cardiac ATP levels were analyzed using a commercially available kit. mRNA levels of glucose transporter 4 (GLUT4), fatty acid binding protein 3 (FABP3), palmitoyl transferase 1α (CPT-1α), acyl-CoA oxidase 1 (AOX1), D-bifunctional protein (DBP), 3-ketoacyl-CoA thiolase A (THLA), uncoupling protein (UCP) 2 and UCP3 were investigated by quantitative reverse-transcription polymerase chain reaction. FABP3 protein expression was analyzed by Western blotting. Non-targeted metabolomics by LC-MS/MS was applied to evaluate profile of lipid metabolism in heart.ResultsCompared with controls, EF% and FS% were significantly reduced in diabetic mice. Furthermore, blood myocardial injury indexes and lipids, as well as myocardial mitochondrial cristae fusion were significantly increased. In the diabetic heart, GLUT4 expression was decreased, while expression of FABP3, CPT-1α, AOX1, DBP, THLA, UCP2 and UCP3 was increased, and ATP levels were reduced. In total, 113 lipids exhibited significant differential expression (FC > 2, P < 0.05) between the two groups, with sphingolipid metabolism identified as the top-ranking affected canonical pathway. In the diabetic heart, long-chain hydroxyl-acylcarnitines (8/8) and acylcarnitines (6/11), triglycerides (2/5), and diacyglycerol (3/7) were upregulated, while very long-chain polyunsaturated fatty acids (PUFAs) (5/6) including eicosapentaenoate, docosahexaenoate, phosphocholine (11/19), lysophosphocholine (5/9), phosphoethanolamine (7/11), lysophosphoethanolamine (7/10), phosphatidylglycerol (6/8), phosphoserine (6/8), phosphatidylinositol (2/2), phosphatidic acid (1/1), lysophosphatidic acid (1/1) and sphingomyelin (6/6) were downregulated.ConclusionsOur data suggest that the increase in toxic lipid species and decreased in PUFAs undergoing peroxisomal β-oxidation, combined with the reduction in phospholipids cause mitochondrial injury and subsequent uncoupling of phosphorylation and ATP deficiency; thereby leading to diabetic heart dysfunction.

Toll-interacting protein differentially modulates HIF1α and STAT5-mediated genes in fibroblasts

Toll-interacting protein (Tollip) deficiency has been implicated in complex inflammatory and infectious diseases whose mechanisms are poorly understood. Comparing the gene expression profiles of WT and Tollip-deficient murine embryonic fibroblasts, we observed here that Tollip deficiency selectively reduces the expression of the inflammatory cytokines interleukin 6 (IL-6), IL-12, and tumor necrosis factor α (TNFα) but potentiates the expression of fatty acid-binding protein 4 (FABP4) in these cells. We also observed that expression of hypoxia-inducible factor 1-α (HIF1α) is reduced, whereas that of signal transducer and activator of transcription 5 (STAT5) is elevated, in Tollip-deficient cells, correlating with the decreased expression of inflammatory cytokines and increased expression of FABP4 in these cells. We further found that the coupling of ubiquitin to ER degradation (CUE) domain of Tollip is required for stimulating HIF1α activity, because Tollip CUE-domain mutant cells exhibited reduced levels of HIF1α and selected cytokines. Tollip is known to mediate autophagy and lysosome fusion, and herein we observed that Tollip's autophagy function is required for modulating STAT5 and FABP4 expression. Bafilomycin A, an inhibitor of lysosome fusion, enhanced STAT5 and FABP4 expression in WT fibroblasts, whereas torin 2, an activator of autophagy, reduced STAT5 and FABP4 expression in Tollip-deficient fibroblasts. Taken together, our study reveals that Tollip differentially modulates HIF1α and STAT5 expression in fibroblasts, potentially explaining the complex and context-dependent contribution of Tollip to disease development.

The natural compound GL22, isolated from Ganoderma mushrooms, suppresses tumor growth by altering lipid metabolism and triggering cell death

Cancer cells rewire their metabolism to satisfy the demands of uncontrolled proliferation and survival. The reprogramming of lipid metabolism supports tumor growth, metastasis, and therapy-resistance. Therefore, targeting lipid metabolic reprogramming is a potential cancer treatment strategy. We recently isolated the novel natural triterpene GL22 from Ganoderma leucocontextum, a traditional Chinese medicine. Here, we show that GL22 significantly inhibits the growth of the liver cancer cell line Huh7.5 in vitro and of Huh7.5-derived tumor xenografts in vivo. We further find that GL22 induces mitochondrial dysfunction and cell death in Huh7.5 cells, in part due to fatty acid immobilization and loss of the mitochondrial lipid cardiolipin, which has vital structural and metabolic functions. Importantly, we demonstrate that GL22 treatment decreases the expression of fatty acid-binding proteins (FABPs), which likely underlies the loss of cardiolipin, mitochondrial dysfunction, and cell death. The over-expressions of FABPs prevented the GL22-induced cell death, loss of cardiolipin, decrease of ATP production, and reduction of oxygen consumption rate in Huh7.5 cells. Our results support targeting lipid metabolism via manipulating FABPs as a cancer treatment strategy, and promote Chinese medicine as an important source of novel anticancer drugs.