Expression Of Lipid Metabolism-related Proteins Research Articles

Establishment of a Mouse Model for Porokeratosis Due to Mevalonate Diphosphate Decarboxylase Deficiency.

Porokeratosis (PK) is an autoinflammatory keratinization disease (AIKD) characterized by circular or annular skin lesions with a hyperkeratotic rim, pathologically shown as the cornoid lamella. Four genes that cause PK are associated with the mevalonate (MV) pathway. In Chinese PK patients, mevalonate diphosphate decarboxylase (MVD) is the most common causative gene. The lack of an animal model has greatly limited research on PK pathogenesis. In this research, we constructed K14-CreERT2-Mvdfl/fl mice using the Cre-LoxP system to create a mouse model for in-depth studies of PK. The Epidermal Mvd gene was knocked out by intraperitoneal injection of Tamoxifen (TAM). Pathology, immunohistochemistry, RNA-seq, and Western Blot analysis were performed. Skin lesions appeared following Mvd deficiency, and pathological examination revealed the characteristic cornoid lamella, as well as cutaneous inflammation. Furthermore, we observed elevated levels of IL-17A and IL-1β, and a decreased Loricrin level in epidermal Mvd-deficient mice. Compared with the wild-type (WT) group, Mvd deficiency activated the expression of lipid metabolism-related proteins. We developed the first mouse model for PK research, enabling further studies on disease development and treatment approaches.

Prenatal exposure to low-dose di-(2-ethylhexyl) phthalate (DEHP) induces potentially hepatic lipid accumulation and fibrotic changes in rat offspring

Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer that is widely used to enhance the flexibility and durability of various products. As an endocrine disruptor, DEHP can interfere with normal hormonal functions, posing substantial health risks to organisms. Given the critical role of the liver in DEHP metabolism, we investigated potential liver damage in offspring induced by prenatal exposure to low doses of DEHP in Sprague Dawley rats. Pregnant rats were divided into three groups and administered 20 or 200 μg/kg/day of DEHP or corn oil vehicle control via oral gavage from gestation days 0–20. Male rat offspring were euthanized on postnatal day 84, and blood and liver specimens were collected for analysis. We observed fibrotic changes in the livers of the exposed groups, accompanied by the proliferation and activation of hepatic stellate cells and upregulated expression of TGF-B and collagen 1A1. Additionally, an inflammatory response, characterized by increased macrophage infiltration and elevated levels of pro-inflammatory cytokines, was evident. Third, hepatic and serum triglyceride and serum cholesterol were notably increased, along with upregulated expression of lipid metabolism-related proteins, such as sterol regulatory element-binding protein-1c, acetyl-CoA carboxylase, fatty acid synthase, and diacylglycerol O-acyltransferase 1, particularly in the low-dose group. These results suggest that prenatal exposure to DEHP can disrupt lipid metabolism, resulting in hepatic lipid accumulation in the offspring. This exposure may also induce an inflammatory response that contributes to the development of liver fibrosis. Thus, even at relatively low doses, such exposure can precipitate latent liver damage in offspring.

Lack of Rab27a attenuates foam cell formation and macrophage inflammation in uremic apolipoprotein E knockout mice.

As the most common cardiovascular disease, atherosclerosis (AS), is a leading cause of high mortality in patients with chronic renal failure. Rab27a has been reported to regulate the progression of cardiovascular and renal diseases. Nevertheless, little studies investigated the role and mechanism of Rab27a in uremic-accelerated AS (UAAS). An animal model of UAAS was established in apolipoprotein E knockout (apoE-/-) mice using 5/6 nephrectomy (NX). We conducted in vitro and in vivo functional experiments to explore the role of Rab27a in UAAS, including the presence of oxidized low-density lipoprotein (ox-LDL). Rab27a expression was upregulated in the plaque tissues of NX apoE-/- mice. The knockout of Rab27a (Rab27a-/-) reduced AS-induced artery injury, as manifested by the reductions of plaque area, collagen deposition, inflammation and lipid droplet. Besides, cholesterol efflux was increased, while the expression of lipid metabolism-related proteins and the secretions of pro-inflammatory factors were decreased in ox-LDL-induced NX Rab27a-/- apoE-/-mice group. Further, Rab27a deletion inhibited the activation of nuclear factor κB (NF-κB) pathway. In conclusion, our study indicated that Rab27a deficiency attenuated foam cell formation and macrophage inflammation, depending on the NF-κB pathway activation, to inhibit AS progression in uremic apoE-/- mice. This finding may provide a new targeting strategy for UAAS therapy.

Profiles of lipid, protein and microRNA expression in exosomes derived from intestinal epithelial cells after ischemia-reperfusion injury in a cellular hypoxia model.

Intestinal ischemia-reperfusion injury leads to proinflammatory responses via gut-derived mediators, and accumulating evidence suggests that exosomes secreted by intestinal epithelial cells are involved in the development of systemic inflammation. Studies have reported changes in protein, lipid, and microRNA (miRNA) expression; however, considering the different experimental conditions, information on the relationships among these biomolecules remains insufficient. The aim of this study was to elucidate the multiple changes that simultaneously occur in exosomes after ischemic stimulation. Here, differentiated human intestinal Caco-2 cells were exposed to 95% air (normoxia group) or 5% O2 (hypoxia group) for 6 h. Cells in each group were subsequently incubated for 24 h in an atmosphere of 5% CO2 plus 95% air. The conditioned medium of each group was collected for isolating intestinal epithelial cell-derived exosomes. Together with proteome analyses, lipid analyses, and miRNA quantification, biological functional assays were performed using monocytic NF-κB reporter cells. Lipid metabolism-related protein expression was upregulated, miRNA levels were slightly altered, and unsaturated fatty acid-containing lysophosphatidylcholine concentration increased after hypoxia and reoxygenation injury; this suggested that the changes in exosomal components associated with ischemia-reperfusion injury activates inflammation, including the NF-κB pathway. This study elucidated the multiple changes that co-occur in exosomes after ischemic stimulation and partially clarified the mechanism underlying exosome-mediated inflammation after intestinal ischemic recanalization.

New insight into the role of lipid metabolism-related proteins in rheumatic heart valve disease

PurposeThe aim of this study was to determine the expression of lipid metabolism-related proteins in rheumatic heart valve disease (RHVD).MethodsThis retrospective study involved a total of 20 cases of moderate or severe rheumatic mitral valve stenosis and 4 cases of mitral regurgitation due to secondary causes from September 2018 to September 2021. The patients enrolled included 12 males and 12 females who underwent surgical excision of the mitral valve at the cardiac surgery department of Hainan General Hospital. The samples of mitral valve were collected during surgery treatment as the study group, and mitral valves collected from patients with ischemic heart disease were allocated into the control group. Hematoxylin–eosin (HE), oil red staining and immunohistochemical (IHC) staining were conducted to compare the expression of lipid metabolism-related proteins (ATP-binding cassette transporter A1 and acyl-coenzyme A: cholesterol acyltransferase-1), and real-time polymerase chain reaction (RT–PCR) was applied to compare the mRNA levels of ABCA1, ACAT1, and the inflammatory cytokines TNF-α, IL-10, and MCP-1.ResultsIn general, the rheumatic mitral valve showed leaflet thickening along with border adhesions and visible yellow fats. Oil red O staining also revealed the abovementioned results as well as fat cells. Both ABCA1 and ACAT1 were expressed in the rheumatic mitral valve via IHC, whereas only ACAT1 showed a faint level of expression in the ischemic mitral valve with no expression of ABCA1. In addition, compared with the ischemic mitral valve, RT-PCT showed increased mRNA expression levels of ABCA1, ACAT1, and the inflammatory cytokines TNF-α, IL-10, and MCP-1 (P < 0.05). After dividing the RMs into two groups for RT–PCR, we found that the higher the expression of ABCA1 and ACAT1 was, the lower the relative expression of inflammatory factors.ConclusionThis study showed that adipose tissue, adipose cells, and lipid transport-related proteins were expressed strongly in the rheumatic mitral valve, suggesting that adipose tissue formation might be one of the important pathways in the pathology of rheumatic heart disease. In addition, adipose tissue and adipocytes were also involved in the inflammatory process. These data provide new insight into pathological mechanisms in rheumatic heart disease.

Quantification of Acipimox in Plasma and Tissues by LC-MS/MS: Application to Pharmacokinetic Comparison between Normoxia and Hypoxia.

This study aimed to evaluate the pharmacokinetics of acipimox in rats under simulated high altitude hypoxia conditions. A sensitive and reliable LC–MS/MS method has been established for the quantitation of acipimox in rat plasma and tissue homogenate and validated according to the guidelines of the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA). Western blotting and enzyme linked immunosorbent assay (ELISA) were used to investigate the expression of lipid metabolism-related proteins and free fatty acid (FFA) levels, respectively. Cell viability was detected using a Cell Counting kit-8 assay (CCK-8). The method was then successfully applied in a pharmacokinetic comparison between normoxic and hypoxic rats. The results indicated that there were significant differences in the main pharmacokinetics parameters of acipimox between normoxic and hypoxic rats. HCAR2 expression in the hypoxia group was upregulated compared to that in the normoxia group and the levels of FFA decreased more in the hypoxia group. Under the hypoxia condition, the proliferation of HK2 cells was inhibited with increasing concentrations of acipimox. The results provide important and valuable information for the safety and efficacy of acipimox, which indicated that the dosage of acipimox might be adjusted appropriately during clinical medication in hypoxia.

Comparative effects of black pigmented and non-pigmented brown rice on hypolipidemic activity and their mechanisms of action in high fat diet-induced hamsters

Brown rice consumption is known to have numerous therapeutic benefits. This study aimed to examine the bioactive components of black-pigmented (BRW) and non-pigmented (TK9W) brown rice and their comparative effects on hypolipidemic activity in high-fat diet (HFD)-induced hamsters. The results showed that besides total flavonoids and dietary fibers, BRW displayed higher total phenol and anthocyanin contents than TK9W. At 100 mg/kg/BW, although both BRW and TK9W significantly decreased the levels of serum and hepatic total cholesterols (TC) and triglycerides (TG), and increased the levels of serum high-density lipoprotein cholesterol (HDL-C) and fecal TC in HFD-induced hamsters, BRW was more effective than TK9W in lowering serum low-density lipoprotein cholesterol (LDL-C) and hepatic TG. BRW and TK9W also effectively down-regulated fatty acid synthase and PPARγ, and up-regulated lipoprotein lipase and PPARα expression in liver tissues at this dose level. This study demonstrates that, although BRW appears to have better hypolipidemic activity than TK9W, brown rice of different pigmentation effectively decreased the levels of serum and hepatic TG and TC, increased the serum HDL-C and fecal TC, as well as modulated the lipid metabolism-related protein expression in liver tissues.

Quercetin Attenuates Osteoporosis in Orchiectomy Mice by Regulating Glucose and Lipid Metabolism via the GPRC6A/AMPK/mTOR Signaling Pathway.

Quercetin, a flavonoid found in natural medicines, has shown a role in disease prevention and health promotion. Moreover, because of its recently identified contribution in regulating bone homeostasis, quercetin may be considered a promising agent for improving bone health. This study aimed to elucidate the role of quercetin in androgen deprivation therapy-induced osteoporosis in mice. C57BL/6 mice were subjected to orchiectomy, followed by quercetin treatment (75 and 150 mg/kg/d) for 8 weeks. Bone microstructure was then assessed by micro-computed tomography, and a three-point bending test was used to evaluate the biomechanical parameters. Hematoxylin and eosin (H&E) staining was used to examine the shape of the distal femur, gastrocnemius muscle, and liver. The balance motion ability in mice was evaluated by gait analysis, and changes in the gastrocnemius muscle were observed via Oil red O and Masson’s staining. ELISA and biochemical analyses were used to assess markers of the bone, glucose, and lipid metabolism. Western blotting analyses of glucose and lipid metabolism-related protein expression was performed, and expression of the GPCR6A/AMPK/mTOR signaling pathway-related proteins was also assessed. After 8 weeks of quercetin intervention, quercetin-treated mice showed increased bone mass, bone strength, and improved bone microstructure. Additionally, gait analysis, including stride length and frequency, were significantly increased, whereas a reduction of the stride length and gait symmetry was observed. H&E staining of the gastrocnemius muscle showed that the cross-sectional area of the myofibers had increased significantly, suggesting that quercetin improves balance, motion ability, and muscle mass. Bone metabolism improvement was defined by a reduction of serum levels of insulin, triglycerides, total cholesterol, and low-density lipoprotein, whereas levels of insulin-like growth factor-1 and high-density lipoprotein were increased after quercetin treatment. Expression of proteins involved in glucose uptake was increased, whereas that of proteins involved in lipid production was decreased. Moreover, the GPRC6A and the phospho-AMPK/AMPK expression ratio was elevated in the liver and tibia tissues. In contrast, the phospho-mTOR/mTOR ratio was reduced in the quercetin group. Our findings indicate that quercetin can reduce the osteoporosis induced by testosterone deficiency, and its beneficial effects might be associated with the regulation of glucose metabolism and inhibition of lipid metabolism via the GPCR6A/AMPK/mTOR signaling pathway.

Effects of Naltrexone on Expression of Lipid Metabolism-Related Proteins in Liver Steatosis Induced by Endoplasmic Reticulum Stress in Mice.

This study aimed to explore the effect of naltrexone on the expression of lipid metabolism-related proteins in liver steatosis induced by endoplasmic reticulum stress in mice. Thirty inbred mice (C57BL/6J) were divided into three groups: group A (normal control group), group B (model control), and group C (naltrexone group). The male mice in group A were fed a regular diet, and the mice in groups B and C were fed a high-fat diet. Liver steatosis was observed by histopathological sections. Mouse liver (alanine aminotransferase (ALT) and triglyceride (TC)) content (glucose regulatory protein (GRP78), endoplasmic reticulum transmembrane protein kinase-1α (IRE-1α), C/EBP source protein (CHOP), cysteine-containing aspartate proteolytic enzyme 12 (caspase-12), B lymphoma-2 (Bcl-2), and cell death mediator (Bim)) was detected. Compared with group A, bodyweight, fat weight, ALT, TG, and hepatic steatosis were significantly increased in B and C groups (P < 0.05); compared with group B, group C showed a significant decrease in bodyweight, fat weight, ALT, TG, and hepatic steatosis (P < 0.05). Compared with group A, the expression levels of GRP78, IRE-1α, CHOP, caspase-12, and Bim in liver tissue of groups B and C mice were increased. Bcl-2 decreased (P < 0.05). Compared with group B and group C after naltrexone intervention, the expression levels of GRP78, IRE-1α, CHOP, caspase-12, and Bim decreased significantly, and Bcl-2 increased significantly (P < 0.05). Naltrexone can effectively reduce bodyweight and adipose tissue accumulation, reduce liver fat lesions, improve the expression of lipid metabolism-related proteins and endoplasmic reticulum stress, reduce liver lipid synthesis, and protect liver cells.

Polysaccharide fraction from greens of Raphanus sativus alleviates high fat diet-induced obesity

Radish (Raphanus sativus) greens are commonly used as a vegetable in Korea; however, their anti-obesity effect has not been reported yet. We prepared the polysaccharide fraction of radish greens (PRG) and assessed its anti-obesity activity in high fat diet (HFD)-induced obese C57BL/6J mice. Supplementation with 4 mg/kg PRG reduced weight gain and body fat percentage, and regulated serum biomarkers against HFD-induced obesity. Moreover, PRG treatment improved gut permeability by increasing tight junction protein expression and colon length shortening. HFD intake increased the proportion of Firmicutes and decreased the proportion of Bacteroidetes and Verrucomicrobia; however, PRG supplementation maintained gut microbial composition to normal diet condition. Moreover, PRG reduced HFD-induced increase of lipid metabolism-related protein expression, along with adipocyte size in white adipose tissue. These results indicated that PRG as a potential prebiotic, has anti-obesity properties by improving gut barrier function, modulating gut microbiota and regulating lipid metabolism.

Oligostilbenes extracts from Iris lactea Pall. var. chinensis (Fisch.) Koidz improve lipid metabolism in HFD/STZ-induced diabetic mice and inhibit adipogenesis in 3T3-L1 cells

The present study investigated the anti-diabetic effects of Oligostilbenes extracts (Olie) from Iris lactea Pall. var. chinensis (Fisch.) Koidz (I. lactea) and the potential mechanisms, in high-fat-diet (HFD)-induced diabetic mice and 3T3-L1 adipocytes. Olie are a group of major active extracts from I. lactea that have been used as nutraceutical because of their antioxidant activity. Six-week Olie treatment improved fasting blood glucose levels, as well as blood lipid profiles in HFD/streptozocin (STZ)-induced diabetic mice, compared with non-treated mice. Olie treatment upregulated the levels of phosphorylated of AMPK and lipolysis-related proteins, while the hepatic expression of ACC and FAS in diabetic mice was inhibited. In cultured 3T3-L1 cells, Olie (2−15 μg/mL) treatment dose-dependently suppressed the differentiation into mature adipocytes and lowered cellular lipid accumulation. Consistently, Olie reduced expression of adipogenic transcription factors including CCAAT/enhancer-binding protein β (C/EBPβ) and peroxisome proliferator-activated receptor γ (PPARγ). In addition, mitochondrial function in 3T3-L1 adipocytes was improved after Olie treatment. Taken together, our findings indicate that a lipid-lowering effect of Olie in HFD/STZ-induced diabetic mice and adipogenesis/ lipogenesis suppressing effect in 3T3-L1 cells, via regulating the expression of lipid metabolism-related proteins.

Consumption of salt leads to ameliorate symptoms of metabolic disorder and change of gut microbiota.

Metabolic diseases caused by high-carbohydrate and/or high-salt diets are becoming major public health concerns. However, the effects of salt on high-carbohydrate diet-induced obesity are unclear. Accordingly, in this study, we investigated the effects of high-salt intake on high-carbohydrate diet-induced obesity. We performed a 12-week study on gut microbiota and metabolic changes in high-rice diet (HRD) or HRD supplemented with high-salt (HRS)-fed C57BL/6J mice by 16S rRNA analysis, glucose and insulin tolerance testing, gut barrier function, western blot and histological analysis. Moreover, the effects of salt on lipid metabolism were confirmed in vitro using 3T3-L1 cells. High salt intake decreased HRD-induced increases in body and white adipose tissue (WAT) weight. Alternatively, HRS did not reverse the observed increases in glucose intolerance and insulin resistance. Moreover, HRD caused changes in the gut microbiota, thereby impairing gut barrier function and increasing inflammation in the liver. HRS altered HRD-induced microbial composition, however, did not ameliorate gut barrier dysfunction or hepatic inflammation. HRS diets regulated the HRD-induced increase in peroxisome proliferator-activated receptor-γ (PPAR-γ) and lipid metabolism-related protein expression. Moreover, within WAT, HRS was found to reverse the observed decrease in adiponectin and increase in PPAR-γ expression induced by HRD. In vitro, high NaCl concentration also significantly reduced 3T3-L1 cell differentiation and modulated lipid metabolism without causing cytotoxicity. These results indicate that high salt intake ameliorates metabolic changes associated with a high-rice diet, including changes in fecal microbiota composition.

Ezetimibe promotes CYP7A1 and modulates PPARs as a compensatory mechanism in LDL receptor-deficient hamsters

BackgroundThe LDL-C lowering effect of ezetimibe has been attributed primarily to increased catabolism of LDL-C via up-regulation of LDL receptor (LDLR) and decreased cholesterol absorption. Recently, ezetimibe has been demonstrated to have reverse cholesterol transport (RCT) promoting effects in mice, hamsters and humans. However, the underlying mechanisms are still not clear. The aim of this study is to investigate whether ezetimibe improves RCT-related protein expression in LDLR−/− hamsters.MethodsA high-fat diet was used to induce a human-like hyperlipidemia in LDLR−/− hamsters. Lipid profiles were assayed by commercially available kits, and the effects of ezetimibe on lipid metabolism-related protein expression were carried out via western blot.ResultsOur data demonstrated that ezetimibe administration significantly reduced plasma total cholesterol (~ 51.6% reduction, P < 0.01) and triglyceride (from ~ 884.1 mg/dL to ~ 277.3 mg/dL) levels in LDLR−/− hamsters fed a high-fat diet. Ezetimibe administration (25 mg/kg/d) significantly promoted the protein expression of cholesterol 7 alpha-hydroxylase A1 (CYP7A1), LXRβ and peroxisome proliferator-activated receptor (PPAR) γ; and down-regulated the protein expression of PPARα and PPARβ. However, it showed no significant effect on sterol regulatory element-binding protein (SREBP)-1c, SREBP-2, proprotein convertase subtilisin/kexin type 9 (PCSK9), Niemann-Pick C1-like 1 (NPC1L1), and ATP-biding cassette (ABC) G5/G8.ConclusionEzetimibe may accelerate the transformation from cholesterol to bile acid via promoting CYP7A1 and thereby enhance RCT. As a compensatory mechanism of TG lowering, ezetimibe promoted the protein expression of PPARγ and decreased PPARα and β. These results are helpful in explaining the lipid-lowering effects of ezetimibe and the potential compensatory mechanisms.

Energy transfer from adipocytes to cancer cells in breast cancer.

Limitations of the current therapeutic approach have raised the need for a novel therapeutic agent in breast cancer. Recently, interest in drugs targeting the tumor microenvironment (TME) had drawn attention in the treatment of breast cancer. Furthermore, recent studies have suggested the role of adipocytes, which are part of the TME, in tumor initiation, growth, and metastasis. In this study, we investigated the metabolic interaction between adipocytes and breast cancer cells and its potential as a new therapeutic target in breast cancer. Breast cancer cell lines and human breast cancer tissue samples were evaluated. Compared to cancer cells cultured alone, or the control group, those co-cultured with adipocytes showed lipid transfer from adipocytes to cancer cells and it was different according to the molecular subtype of breast cancer. Breast cancer cells affected the lipolysis of adipocytes and adipocytes affected the β-oxidation of breast cancer cells. The key molecule of the process was fatty acid binding protein 4 (FABP4), which is combined with free fatty acid (FFA) and supports its migration to cancer cells. When FABP4 was suppressed, lipid transfer between adipocytes and cancer cells, lipolysis of adipocytes, and β-oxidation of breast cancer cells were reduced. Furthermore, the expression of lipid metabolism-related proteins and lipolysis-related proteins in breast cancer with adipose stroma showed significantly different expression according to the region of breast cancer tissue. Taken together, we demonstrated the metabolic interaction between adipocytes and breast cancer cells. Breast cancer cells increase the lipolysis in adipocytes and produce a fatty acid, and fatty acid enters into cancer cells. Also, adipocytes contribute to the survival and growth of cancer cells through increased mitochondrial β-oxidation by using fatty acid from adipocytes. The key molecule of the process is FABP4 and when FABP4 is suppressed, the metabolic interaction is reduced, suggesting its role as a potential therapeutic target.

Biochanin A and CPe-III Peptide Improved Hepatic Inflammation by Regulating the Hepatic Lipid Metabolic Pathways in Diet-Induced Obese Mice

Biochanin A (BCA) and CPe-III peptide, which both exist in chickpea (Cicer arietinum L.), possess significant antihyperlipidemic properties. However, the actual mechanisms of those compounds in inhibiting the dysregulation of lipid metabolism and complicated inflammation have not been well characterized. This study investigated the effects of BCA, CPe-III peptide, and combined BCA and CPe-III peptide (BC) on the expression of genes involved in hepatic lipid and inflammation metabolism. Results demonstrated that BCA, CPe-III peptide, and BC significantly attenuated hepatitis and hyperlipidemia by downregulating those genes involved in pro-inflammatory cytokines (TNF-α), hepatic fatty acid (FA) synthesis (ACC1 and FAS), cholesterol metabolism (SREBP2, HMGCR, and PCSK9), and upregulating key regulators involved in FA oxidation (PPARα and FABP1), lipolysis (ATGL), LDLR, reverse cholesterol transport (ABCA1, SR-B1, and LXRα), and cholesterol catabolism (CYP7A1). Moreover, they also altered the expression of lipid metabolism-related proteins, including SREBP2, PCSK9, LDLR, ABCA1, and CYP7A1. Finally, these results revealed that the combination treatment of BCA and CPe-III peptide resulted in greater antihyperlipidemic activity compared with individual compounds.

Mixture of five herbal extracts ameliorates pioglitazone-induced aggravation of hepatic steatosis via activating the adiponectin receptor 2/AMP-activated protein kinase signal pathway in diabetic KKAy mice

ObjectiveTo assess the effect of a mixture of five herbal extracts (FT-5) on insulin resistance, glucose/lipid metabolism, hepatic steatosis, and to investigate whether the combination of FT-5 and pioglitazone would provide a robust effect on diabetes treatment, while may minimize undesirable side-effects of pioglitazone in diabetic Ay gene (KKAy) mice. MethodsSeven-week-old KKAy mice were randomly divided into five groups: control (CON) group, FT-5 (2.0 g/kg) group, pioglitazone (20 mg/kg) (PIO) group, pioglitazone (20 mg/kg)+FT-5 (2.0 g/kg) (P+F) group. Age-matched C57BL/6J mice were used as the control group. After seven weeks of continuous intragastric administration of medication, the glucose metabolism, insulin sensitivity and lipid metabolism of KKAy mice were evaluated by assessing the fasting blood glucose (FBG), oral glucose tolerance test (OGTT), fasting serum insulin (FINS), insulin tolerance test (ITT), homeostasis model of assessment-insulin resistance index (HOMA-IR), total cholesterol (TC), total triglycerides (TG), and free fatty acids (FFA) in plasma and liver. Plasma and hepatic adiponectin were measured via enzyme-linked immunosorbent assays. Genes related to adipogenesis and lipolysis in white adipose tissues (WAT) and liver were examined by real-time polymerase chain reaction. Lipid metabolism-related protein expression in the liver of KKAy mice were detected by western blotting. ResultsPIO treatment remarkably improved insulin resistance. However, it also showed substantial side effects. FT-5 group exhibited no significant decrease in serum glucose. However, it reduced fasting plasma TG levels and improved hepatic steatosis of KKAy mice. P + F group showed improved insulin resistance and similar body weight gain, as compared with control group. The mRNA expression of genes related to fatty acid oxidation was markedly up-regulated in the liver of P + F group. Pioglitazone administration markedly decreased the phosphorylation levels of AMPK, as compared with all other groups. Besides, even though plasma adiponectin increased in PIO, FT-5, P + F group, adipoR2 gene expression significantly decreased in the liver of PIO group. ConclusionFT-5 decreased plasma TG and alleviated aggravating hepatic steatosis induced by pioglitazone in KKAy mice. FT-5's mechanism might be associated with its ability to activate the AdipoR2/AMPK pathway.

Maternal fat overfeeding programs lack of response to lipid catabolism regulators in the livers of foetuses and offspring, possible implications for lipid overaccumulation

Nonalcoholic fatty liver disease, one of the most common causes of chronic liver disease, is strongly associated with metabolic syndrome. Nordihydroguaiaretic acid (NDGA) has been reported to inhibit lipoprotein lipase; however, the effect of NDGA on hepatic lipid metabolism remains unclear. We evaluated body weight, adiposity, liver histology, and hepatic triglyceride content in high-fat diet (HFD)-fed C57BL/6J mice treated with NDGA. In addition, we characterized the underlying mechanism of NDGA’s effects in HepG2 hepatocytes by Western blot and RT-PCR analysis. NDGA (100 or 200 mg/kg/day) reduced weight gain, fat pad mass, and hepatic triglyceride accumulation, and improved serum lipid parameters in mice fed a HFD for 8 weeks. NDGA significantly increased AMP-activated protein kinase (AMPK) phosphorylation in the liver and in HepG2 hepatocytes. NDGA downregulated the level of mature SREBP-1 and its target genes (acetyl-CoA carboxylase and fatty acid synthase), but, it upregulated expression of genes involved in fatty acid oxidation, such as peroxisome proliferator-activated receptor (PPAR)α, PPARγ coactivator-1, carnitine palmitoyl transferase-1, and uncoupling protein-2. The specific AMPK inhibitor compound C attenuated the effects of NDGA on expression of lipid metabolism-related proteins in HepG2 hepatocytes. The beneficial effects of NDGA on HFD-induced hepatic triglyceride accumulation are mediated through AMPK signaling pathways, suggesting a potential target for preventing NAFLD.

Naltrexone changes the expression of lipid metabolism-related proteins in the endoplasmic reticulum stress induced hepatic steatosis in mice.

Endoplasmic reticulum (ER) stress is closely associated with several chronic diseases such as obesity, atherosclerosis, type 2 diabetes, and hepatic steatosis. Steatosis in hepatocytes may also lead to disorders such as nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH), fibrosis, and possibly cirrhosis. Opioid peptides are involved in triglyceride and cholesterol dysregulation. Naltrexone also attenuates ER stress induced hepatic steatosis in mice. In this study, we evaluated the effects of naltrexone on the expression of lipid metabolism-related nuclear factors and enzymes in the ER stress induced hepatic steatosis. C57/BL6 mice received saline, DMSO and naltrexone as control groups. In a fourth group, ER stress was induced by tunicamycin (TM) injection and in the last group, naltrexone was given before TM administration. Histopathological evaluations, real-time RT-PCR and western blot were performed. We found that GRP78, IRE1α, PERK and ATF6 gene expression and steatosis significantly reduced in naltrexone treated animals. Naltrexone alleviated the gene and protein expression of SREBP1c. Expression of ACAT1, apolipoprotein B (ApoB) and PPARα also increased after naltrexone treatment. In conclusion, this study, for the first time, shows that naltrexone has a considerable role in attenuation of ER stress-induced liver injury.

Expression of Lipid Metabolism-Related Proteins Differs between Invasive Lobular Carcinoma and Invasive Ductal Carcinoma.

We comparatively investigated the expression and clinical implications of lipid metabolism-related proteins in invasive lobular carcinoma (ILC) and invasive ductal carcinoma (IDC) of the breast. A total of 584 breast cancers (108 ILC and 476 IDC) were subjected to tissue microarray and immunohistochemical analysis for lipid metabolism-related proteins including hormone-sensitive lipase (HSL), perilipin A, fatty acid binding protein (FABP)4, carnitine palmitoyltransferase (CPT)-1, acyl-CoA oxidase 1, and fatty acid synthetase (FASN). HSL, perilipin A, and FABP4 expression (all p < 0.001) differed significantly: HSL and FABP4 were more frequently present in ILC, whereas perilipin A was more frequently detected in IDC. Among all invasive cancers, HSL and FABP4 were highly expressed in luminal A-type ILC (p < 0.001) and perilipin A in luminal A-type IDC (p = 0.007). Among luminal B-type cancers, HSL and FABP4 were more highly expressed in ILC (p < 0.001). Univariate analysis found associations of shorter disease-free survival with CPT-1 positivity (p = 0.004) and acyl-CoA oxidase 1 positivity (p = 0.032) and of shorter overall survival with acyl-CoA oxidase 1 positivity (p = 0.027). In conclusion, ILC and IDC exhibited different immunohistochemical lipid metabolism-related protein expression profiles. Notably, ILC exhibited high HSL and FABP4 and low perilipin A expression.

Expression of lipid metabolism-related proteins in breast phyllodes tumors.

The aim of this study was to investigate the expression of lipid metabolism-related proteins and the implications thereof in phyllodes tumor (PT) of the breast. Atissue microarray (TMA) was constructed using paraffin blocks from 194 PT patient tissue samples. Immunohistochemical staining for lipid metabolism-related proteins, namely hormone-sensitive lipase (HSL), perilipin 2, fatty-acid-binding proteins 4 (FABP4), carnitine palmitoyltransferase-1 (CPT-1), acyl-CoA oxidase 1 (ACOX-1), and fatty acid synthase (FASN) was performed, and the immunohistochemical staining results were analyzed with respect to clinicopathologic parameters. The numbers of benign, borderline, and malignant PTs were 151, 27, and 16, respectively. The expression of HSL, perilipin 2, FABP4, CPT-1, and FASN in stromal components was higher in higher grade tumors. On univariate analysis, shorter disease-free survival (DFS) was associated with stromal perilipin 2 positivity (p<0.001) and stromal CPT-1 positivity (p=0.004). Shorter overall survival (OS) was associated with stromal perilipin 2 positivity (p<0.001), stromal FABP4 positivity (p<0.001), stromal CPT-1 positivity (p=0.004), and stromal FASN positivity (p<0.001). Multivariate Cox analysis revealed that stromal perilipin 2 positivity (hazard ratio=31.693, 95% CI: 1.341-748.8, p=0.032) was an independent factor for shorter DFS. In conclusion, higher expressions of HSL, perilipin 2, FABP4, CPT-1 and FASN in the stromal component were observed in higher grade PT.